List of interface bit rates

This is a list of interface bit rates, is a measure of information transfer rates, or digital bandwidth capacity, at which digital interfaces in a computer or network can communicate over various kinds of buses and channels. The distinction can be arbitrary between a computer bus, often closer in space, and larger telecommunications networks. Many device interfaces or protocols (e.g., SATA, USB, SAS, PCIe) are used both inside many-device boxes, such as a PC, and one-device-boxes, such as a hard drive enclosure. Accordingly, this page lists both the internal ribbon and external communications cable standards together in one sortable table.

Factors limiting actual performance, criteria for real decisions

Most of the listed rates are theoretical maximum throughput measures; in practice, the actual effective throughput is almost inevitably lower in proportion to the load from other devices (network/bus contention), physical or temporal distances, and other overhead in data link layer protocols etc. The maximum goodput (for example, the file transfer rate) may be even lower due to higher layer protocol overhead and data packet retransmissions caused by line noise or interference such as crosstalk, or lost packets in congested intermediate network nodes. All protocols lose something, and the more robust ones that deal resiliently with very many failure situations tend to lose more maximum throughput to get higher total long term rates.

Device interfaces where one bus transfers data via another will be limited to the throughput of the slowest interface, at best. For instance, SATA revision 3.0 (6 Gbit/s) controllers on one PCI Express 2.0 (5 Gbit/s) channel will be limited to the 5 Gbit/s rate and have to employ more channels to get around this problem. Early implementations of new protocols very often have this kind of problem. The physical phenomena on which the device relies (such as spinning platters in a hard drive) will also impose limits; for instance, no spinning platter shipping in 2009 saturates SATA revision 2.0 (3 Gbit/s), so moving from this 3 Gbit/s interface to USB 3.0 at 4.8 Gbit/s for one spinning drive will result in no increase in realized transfer rate.

Contention in a wireless or noisy spectrum, where the physical medium is entirely out of the control of those who specify the protocol, requires measures that also use up throughput. Wireless devices, BPL, and modems may produce a higher line rate or gross bit rate, due to error-correcting codes and other physical layer overhead. It is extremely common for throughput to be far less than half of theoretical maximum, though the more recent technologies (notably BPL) employ preemptive spectrum analysis to avoid this and so have much more potential to reach actual gigabit rates in practice than prior modems.

Another factor reducing throughput is deliberate policy decisions made by Internet service providers that are made for contractual, risk management, aggregation saturation, or marketing reasons. Examples are rate limiting, bandwidth throttling, and the assignment of IP addresses to groups. These practices tend to minimize the throughput available to every user, but maximize the number of users that can be supported on one backbone.

Furthermore, chips are often not available in order to implement the fastest rates. AMD, for instance, does not support the 32-bit HyperTransport interface on any CPU it has shipped as of the end of 2009. Additionally, WiMAX service providers in the US typically support only up to 4 Mbit/s as of the end of 2009.

Choosing service providers or interfaces based on theoretical maxima is unwise, especially for commercial needs. A good example is large scale data centers, which should be more concerned with price per port to support the interface, wattage and heat considerations, and total cost of the solution. Because some protocols such as SCSI and Ethernet now operate many orders of magnitude faster than when originally deployed, scalability of the interface is one major factor, as it prevents costly shifts to technologies that are not backward compatible. Underscoring this is the fact that these shifts often happen involuntarily or by surprise, especially when a vendor abandons support for a proprietary system.


By convention, bus and network data rates are denoted either in bits per second (bit/s) or bytes per second (B/s). In general, parallel interfaces are quoted in B/s and serial in bit/s. The more commonly used is shown below in bold type.

On devices like modems, bytes may be more than 8 bits long because they may be individually padded out with additional start and stop bits; the figures below will reflect this. Where channels use line codes (such as Ethernet, Serial ATA and PCI Express), quoted rates are for the decoded signal.

The figures below are simplex data rates, which may conflict with the duplex rates vendors sometimes use in promotional materials. Where two values are listed, the first value is the downstream rate and the second value is the upstream rate.

All quoted figures are in metric decimal units. Note that these aren't the traditional binary prefixes for memory size. These decimal prefixes have long been established in data communications. This occurred before 1998 when IEC and other organizations introduced new binary prefixes and attempted to standardize their use across all computing applications.


The figures below are grouped by network or bus type, then sorted within each group from lowest to highest bandwidth; gray shading indicates a lack of known implementations.

Time Signal Station to Radio Clock

Technology Max. rate Year
IRIG and related 1 bit/s ~0.125 characters/s[1][2] ?

Teletypewriter (TTY) or telecommunications device for the deaf (TDD)

TechnologyMax. rateYear
TTY (V.18)45.4545 bit/s6 characters/s[3]?
TTY (V.18)50 bit/s6.6 characters/s?
NTSC Line 21 Closed Captioning1 kbit/s~100 characters/s?

Modems (narrowband and broadband)

Narrowband (POTS: 4 kHz channel)

TechnologyRateRate ex. overheadYear
Morse code (skilled operator) 0.021 kbit/s[4] 4 characters per second (~40 wpm)[5] 1844
Teleprinter (50 baud) 0.05 kbit/s 404 operations per minute 1940x
Modem 110 baud (Bell 101) 0.11 kbit/s 0.010 kB/s (~10 cps)[6] 1959
Modem 300 (300 baud; Bell 103 or V.21) 0.3 kbit/s 0.03 kB/s (~30 cps)[6] 1962[7]
Modem 1200/75 (600 baud; V.23) 1.2/0.075 kbit/s 0.12/0.0075 kB/s (~120 cps)[6] 1964(?)[8]
Modem 1200 (600 baud; Vadic VA3400, Bell 212A, or V.22) 1.2 kbit/s 0.12 kB/s (~120 cps)[6] 1976
Modem 2400 (600 baud; V.22bis) 2.4 kbit/s 0.3 kB/s[6] 1984[8]
Modem 4800/75 (1600 baud; V.27ter) 4.8/0.075 kbit/s 0.6/0.0075 kB/s[6] 1976[8]
Modem 9600 (2400 baud; V.32) 9.6 kbit/s 1.2 kB/s[6] 1984[8]
Modem 14.4 (2400 baud; V.32bis) 14.4 kbit/s 1.8 kB/s[6] 1991[7]
Modem 28.8 (3200 baud; V.34-1994) 28.8 kbit/s 3.6 kB/s[6] 1994
Modem 33.6 (3429 baud; V.34-1996/98) 33.6 kbit/s 4.2 kB/s[6] 1996[8]
Modem 56k (8000/3429 baud; V.90) 56.0/33.6 kbit/s[9] 7/4.2 kB/s 1998
Modem 56k (8000/8000 baud; V.92) 56.0/48.0 kbit/s[9] 7/6 kB/s 2001
Modem data compression (variable; V.92/V.44) 56.0–320.0 kbit/s[9] 7–40 kB/s 2000[8]
ISP-side text/image compression (variable) 56.0–1000.0 kbit/s 7–125 kB/s 1998[8]
ISDN Basic Rate Interface (single/dual channel) 64/128 kbit/s[10] 8/16 kB/s 1986[11]
IDSL (dual ISDN + 16 kbit/s data channels) 144 kbit/s 18 kB/s 2000[12]

Broadband (hundreds of kHz to GHz wide)

TechnologyRateRate ex. overheadYear
ADSL (G.lite) 1536/512 kbit/s 192/64 kB/s 1998
HDSL ITU G.991.1 a.k.a. DS1 1544 kbit/s 193 kB/s 1998[13]
MSDSL 2000 kbit/s 250 kB/s ?
SDSL 2320 kbit/s 290 kB/s ?
SHDSL ITU G.991.2 5690 kbit/s 711 kB/s 2001
ADSL (G.dmt) ITU G.992.1 8192/1024 kbit/s 1024/128 kB/s 1999
ADSL2 ITU G.992.3 12288/1440 kbit/s 1536/180 kB/s 2002
ADSL2+ ITU G.992.5 24576/3584 kbit/s 3072/448 kB/s 2003
DOCSIS 1.0[14] (cable modem) 38/9 Mbit/s 4.75/1.125 MB/s 1997
DOCSIS 2.0[15] (cable modem) 38/27 Mbit/s 4.75/3.375 MB/s 2002
VDSL ITU G.993.1 52 Mbit/s 7 MB/s 2001
VDSL2 ITU G.993.2 100 Mbit/s 12.5 MB/s 2006
Uni-DSL 200 Mbit/s 25 MB/s 2006
VDSL2 ITU G.993.2 Amendment 1 (11/15) 300 Mbit/s 37.5 MB/s 2015
BPON (G.983) fiber optic service 622/155 Mbit/s 77.7/19.3 MB/s 2005[16] ITU G.9700 1000 Mbit/s 125 MB/s 2014
EPON (802.3ah) fiber optic service 1000/1000 Mbit/s 125/125 MB/s 2008
DOCSIS 3.0[17] (cable modem) 1216/216 Mbit/s 152/27 MB/s 2006
GPON (G.984) fiber optic service 2488/1244 Mbit/s 311/155.5 MB/s 2008[18]
DOCSIS 3.1[19] (cable modem) 10/2 Gbit/s 1.25/0.25 GB/s 2013
10G-PON (G.987) fiber optic service 10/2.5 Gbit/s 1.25/0.3125 GB/s 2012[20]
XGS-PON (G.9807.1) fiber optic service 10/10 Gbit/s 1.25/1.25 GB/s 2016
DOCSIS 3.1 Full Duplex (cable modem) 10/10 Gbit/s 1.25/1.25 GB/s 2017
NG-PON2 (G.989) fiber optic service 40/10 Gbit/s 5/1.25 GB/s 2015[21]

Mobile telephone interfaces

Technology Download rate Upload rate Year
GSM CSD (2G) 14.4 kbit/s[22] 1.8 kB/s 14.4 kbit/s 1.8 kB/s
HSCSD 57.6 kbit/s 5.4 kB/s 14.4 kbit/s 1.8 kB/s
GPRS (2.5G) 57.6 kbit/s 7.2 kB/s 28.8 kbit/s 3.6 kB/s
WiDEN 100 kbit/s 12.5 kB/s 100 kbit/s 12.5 kB/s
CDMA2000 1×RTT 153 kbit/s 18 kB/s 153 kbit/s 18 kB/s
EDGE (2.75G) (type 1 MS) 236.8 kbit/s 29.6 kB/s 236.8 kbit/s 29.6 kB/s 2002
UMTS 3G 384 kbit/s 48 kB/s 384 kbit/s 48 kB/s
EDGE (type 2 MS) 473.6 kbit/s 59.2 kB/s 473.6 kbit/s 59.2 kB/s
EDGE Evolution (type 1 MS) 1184 kbit/s 148 kB/s 474 kbit/s 59 kB/s
EDGE Evolution (type 2 MS) 1894 kbit/s 237 kB/s 947 kbit/s 118 kB/s
1×EV-DO rev. 0 2457 kbit/s 307.2 kB/s 153 kbit/s 19 kB/s
1×EV-DO rev. A 3.1 Mbit/s 397 kB/s 1.8 Mbit/s 230 kB/s
1×EV-DO rev. B 14.7 Mbit/s 1837 kB/s 5.4 Mbit/s 675 kB/s
HSPA (3.5G) 13.98 Mbit/s 1706 kB/s 5.760 Mbit/s 720 kB/s
4×EV-DO Enhancements (2×2 MIMO) 34.4 Mbit/s 4.3 MB/s 12.4 Mbit/s 1.55 MB/s
HSPA+ (2×2 MIMO) 42 Mbit/s 5.25 MB/s 11.5 Mbit/s 1.437 MB/s
15×EV-DO rev. B 73.5 Mbit/s 9.2 MB/s 27 Mbit/s 3.375 MB/s
UMB (2×2 MIMO) 140 Mbit/s 17.5 MB/s 34 Mbit/s 4.250 MB/s
LTE (2×2 MIMO) 173 Mbit/s 21.625 MB/s 58 Mbit/s 7.25 MB/s 2004
UMB (4×4 MIMO) 280 Mbit/s 35 MB/s 68 Mbit/s 8.5 MB/s
EV-DO rev. C 280 Mbit/s 35 MB/s 75 Mbit/s 9 MB/s
LTE (4×4 MIMO) 326 Mbit/s 40.750 MB/s 86 Mbit/s 10.750 MB/s

Wide area networks

56k line56 kbit/s7 KB/s1990
DS064 kbit/s8 KB/s
G.lite (a.k.a. ADSL Lite)1.536/0.512 Mbit/s0.192/0.064 MB/s
DS1 / T1 (and ISDN Primary Rate Interface)1.544 Mbit/s0.192 MB/s1990
E1 (and ISDN Primary Rate Interface)2.048 Mbit/s0.256 MB/s
G.SHDSL2.304 Mbit/s0.288 MB/s
LR-VDSL2 (4 to 5 km [long-]range) (symmetry optional)4 Mbit/s0.512 MB/s
SDSL[23]2.32 Mbit/s0.29 MB/s
T26.312 Mbit/s0.789 MB/s
ADSL[24]8.0/1.024 Mbit/s1.0/0.128 MB/s
E28.448 Mbit/s1.056 MB/s
ADSL212/3.5 Mbit/s1.5/0.448 MB/s
Satellite Internet[25]16/1 Mbit/s2.0/0.128 MB/s
ADSL2+24/3.5 Mbit/s3.0/0.448 MB/s
E334.368 Mbit/s4.296 MB/s
DOCSIS 1.0 (cable modem)[14]38/9 Mbit/s4.75/1.125 MB/s
DOCSIS 2.0 (cable modem)[15]38/27 Mbit/s4.75/3.38 MB/s
DS3 / T3 ('45 Meg')44.736 Mbit/s5.5925 MB/s
STS-1 / OC-1 / STM-051.84 Mbit/s6.48 MB/s
VDSL (symmetry optional)100 Mbit/s12.5 MB/s
OC-3 / STM-1155.52 Mbit/s19.44 MB/s
VDSL2 (symmetry optional)250 Mbit/s31.25 MB/s
T4274.176 Mbit/s34.272 MB/s
T5400.352 Mbit/s50.044 MB/s
OC-9466.56 Mbit/s58.32 MB/s
OC-12 / STM-4622.08 Mbit/s77.76 MB/s
OC-18933.12 Mbit/s116.64 MB/s
DOCSIS 3.0 (cable modem)[17]1216/216 Mbit/s152/27 MB/s
OC-241.244 Gbit/s155.5 MB/s
OC-361.900 Gbit/s237.5 MB/s
OC-48 / STM-162.488 Gbit/s311.04 MB/s
OC-964.976 Gbit/s622.08 MB/s
OC-192 / STM-649.953 Gbit/s1.244125 GB/s
10 Gigabit Ethernet WAN PHY9.953 Gbit/s1.244125 GB/s
DOCSIS 3.1 (cable modem)10/2 Gbit/s1.25/0.25 GB/s
DOCSIS 3.1 Full Duplex (cable modem)10/10 Gbit/s1.25/1.25 GB/s
OC-25613.271 Gbit/s1.659 GB/s
OC-768 / STM-25639.813 Gbit/s4.976 GB/s
OC-1536 / STM-51279.626 Gbit/s9.953 GB/s
OC-3072 / STM-1024159.252 Gbit/s19.907 GB/s

Local area networks

LocalTalk230 kbit/s28.8 kB/s1988
Econet800 kbit/s100 kB/s1981
Omninet1 Mbit/s125 kB/s1980
IBM PC Network2 Mbit/s250 kB/s1985
ARCNET (Standard)2.5 Mbit/s312.5 kB/s1977
Chaosnet (Original)4 Mbit/s3.0 Mbit/s1971
Token Ring (Original)4 Mbit/s500 kB/s1985
Ethernet (10BASE-X)10 Mbit/s1.25 MB/s1980 (1985 IEEE Standard)
Token Ring (Later)16 Mbit/s2 MB/s1989
ARCnet Plus20 Mbit/s2.5 MB/s1992
TCNS100 Mbit/s12.5 MB/s1993?
100VG100 Mbit/s12.5 MB/s1995
Token Ring IEEE 802.5t100 Mbit/s12.5 MB/s
Fast Ethernet (100BASE-X)100 Mbit/s12.5 MB/s1995
FDDI100 Mbit/s12.5 MB/s
MoCA 1.0[26]100 Mbit/s12.5 MB/s
MoCA 1.1[26]175 Mbit/s21.875 MB/s
HomePlug AV200 Mbit/s25 MB/s2005
FireWire (IEEE 1394) 400[27][28]400 Mbit/s50 MB/s1995
HIPPI800 Mbit/s100 MB/s
IEEE 19011000 Mbit/s125 MB/s2010
Token Ring IEEE 802.5v1 Gbit/s125 MB/s2001
Gigabit Ethernet (1000BASE-X)1 Gbit/s125 MB/s1998
Reflective memory or RFM2 (1.25 µs latency)2 Gbit/s170 MB/s2017
Myrinet 20002 Gbit/s250 MB/s
Infiniband SDR 1×[29]2 Gbit/s250 MB/s2001
RapidIO Gen1 1×2.5 Gbit/s312.5 MB/s2000
2.5 Gigabit Ethernet (2.5GBASE-T)2.5 Gbit/s312.5 MB/s2016
Quadrics QsNetI3.6 Gbit/s450 MB/s
Infiniband DDR 1×[29]4 Gbit/s500 MB/s2005
RapidIO Gen2 1×5 Gbit/s625 MB/s2008
5 Gigabit Ethernet (5GBASE-T)5 Gbit/s625 MB/s2016
Infiniband QDR 1×[29]8 Gbit/s1 GB/s2007
Infiniband SDR 4×[29]8 Gbit/s1 GB/s
Quadrics QsNetII8 Gbit/s1 GB/s
RapidIO Gen1 4x10 Gbit/s1.25 GB/s
RapidIO Gen2 2x10 Gbit/s1.25 GB/s2008
10 Gigabit Ethernet (10GBASE-X)10 Gbit/s1.25 GB/s2002-2006
Myri 10G10 Gbit/s1.25 GB/s
Infiniband FDR-10 1×[30]10.31 Gbit/s1.29 GB/s
NUMAlink 312.8 Gbit/s1.6 GB/s2004
Infiniband FDR 1×[30]13.64 Gbit/s1.7 GB/s2011
Infiniband DDR 4×[29]16 Gbit/s2 GB/s2005
RapidIO Gen2 4x20 Gbit/s2.5 GB/s2008
Scalable Coherent Interface (SCI) Dual Channel SCI, x8 PCIe20 Gbit/s2.5 GB/s
Infiniband SDR 12×[29]24 Gbit/s3 GB/s
RapidIO Gen4 1×24.63 Gbit/s3.079 GB/s2016
Infiniband EDR 1×[30]25 Gbit/s3.125 GB/s2014
25 Gigabit Ethernet (25GBASE-X)25 Gbit/s3.125 GB/s2016
NUMAlink 425.6 Gbit/s3.2 GB/s2004
Infiniband QDR 4×[29]32 Gbit/s4 GB/s2007
RapidIO Gen2 8x40 Gbit/s5 GB/s2008
40 Gigabit Ethernet (40GBASE-X) 4×40 Gbit/s5 GB/s2010
Infiniband FDR-10 4×[30]41.25 Gbit/s5.16 GB/s
Infiniband DDR 12×[29]48 Gbit/s6 GB/s2005
Infiniband HDR 1×[31]50 Gbit/s6.250 GB/s[30]2017
NUMAlink 653.6 Gbit/s6.7 GB/s2012
Infiniband FDR 4×[30]54.54 Gbit/s6.82 GB/s2011
RapidIO Gen2 16×80 Gbit/s10 GB/s2008
Infiniband QDR 12×[29]96 Gbit/s12 GB/s2007
Infiniband EDR 4×[30]100 Gbit/s12.5 GB/s2014
100 Gigabit Ethernet (100GBASE-X) 10×/4×100 Gbit/s12.5 GB/s2010/2018
Omni-Path100 Gbit/s12.5 GB/s2015
Infiniband FDR-10 12×[30]123.75 Gbit/s15.47 GB/s
NUMAlink 7159.52 Gbit/s19.94 GB/s2014
Infiniband FDR 12×[30]163.64 Gbit/s20.45 GB/s2011
Infiniband HDR 4×[31]200 Gbit/s25 GB/s[30]2017
200 Gigabit Ethernet (200GBASE-X)200 Gbit/s25 GB/s2017
Infiniband EDR 12×[30]300 Gbit/s37.5 GB/s2014
400 Gigabit Ethernet (400GBASE-X)400 Gbit/s50 GB/s2017
Infiniband HDR 12×[31]600 Gbit/s75 GB/s[30]2017

Wireless networks

802.11 networks in infrastructure mode are half-duplex; all stations share the medium. In infrastructure or access point mode, all traffic has to pass through an Access Point (AP). Thus, two stations on the same access point that are communicating with each other must have each and every frame transmitted twice: from the sender to the access point, then from the access point to the receiver. This approximately halves the effective bandwidth.

802.11 networks in ad hoc mode are still half-duplex, but devices communicate directly rather than through an access point. In this mode all devices must be able to "see" each other, instead of only having to be able to "see" the access point.

Classic WaveLAN2 Mbit/s250 kB/s1988
IEEE 802.112 Mbit/s250 kB/s1997
RONJA (full duplex)10 Mbit/s1.25 MB/s2001
IEEE 802.11a54 Mbit/s6.75 MB/s1999
IEEE 802.11b11 Mbit/s1.375 MB/s1999
IEEE 802.11g54 Mbit/s6.75 MB/s2003
IEEE 802.16 (WiMAX)70 Mbit/s8.75 MB/s2004
IEEE 802.11g with Super G by Atheros108 Mbit/s13.5 MB/s2003
IEEE 802.11g with 125 High Speed Mode by Broadcom125 Mbit/s15.625 MB/s2003
IEEE 802.11g with Nitro by Conexant140 Mbit/s17.5 MB/s2003
IEEE 802.11n (aka Wi-Fi 4)600 Mbit/s75 MB/s2009
IEEE 802.11ac (aka Wi-Fi 5)6.8–6.93 Gbit/s850–866.25 MB/s2012
IEEE 802.11ad7.14–7.2 Gbit/s892.5–900 MB/s2011
IEEE 802.11ax (aka Wi-Fi 6)11 Gbit/s1375 MB/s2019

Wireless personal area networks

ANT20 kbit/s2.5 kB/s
IrDA-Control72 kbit/s9 kB/s
IrDA-SIR115.2 kbit/s14 kB/s
802.15.4 (2.4 GHz)250 kbit/s31.25 kB/s
Bluetooth 1.11 Mbit/s125 kB/s2002
Bluetooth 2.0+EDR3 Mbit/s375 kB/s2004
IrDA-FIR4 Mbit/s500 kB/s
IrDA-VFIR16 Mbit/s2 MB/s
Bluetooth 3.025 Mbit/s3.125 MB/s2009
Bluetooth 4.025 Mbit/s3.125 MB/s2010
Bluetooth 5.050 Mbit/s6.25 MB/s2016
IrDA-UFIR96 Mbit/s12 MB/s
WUSB-UWB480 Mbit/s60 MB/s
IrDA-Giga-IR1024 Mbit/s128 MB/s

Computer buses

Main buses

I²C3.4 Mbit/s425 kB/s1992 (standardized)
Apple II series (incl. Apple IIGS) 8-bit/1 MHz8 Mbit/s1 MB/s[32][33]1977
SS-50 Bus 8-bit/1(?) MHz8 Mbit/s1 MB/s1975
STD-80 8-bit/8 MHz16 Mbit/s2 MB/s
ISA 8-Bit/4.77 MHz0 W/S: every 4 clocks 8 bits
1 W/S: every 5 clocks 8 bits
0 W/S: every 4 clocks 1 byte
1 W/S: every 5 clocks 1 byte
1981 (created)
STD-80 16-bit/8 MHz32 Mbit/s4 MB/s
I3C (HDR mode)[34]33.3 Mbit/s4.16 MB/s2017
Zorro II 16-bit/7.14 MHz[35]42.4 Mbit/s5.3 MB/s1986
ISA 16-Bit/8.33 MHz66.64 Mbit/s8.33 MB/s1984 (created)
Europe Card Bus 8-Bit/10 MHz66.7 Mbit/s8.33 MB/s1977 (created)
S-100 bus 8-bit/10 MHz80 Mbit/s10 MB/s1976 (published)
Serial Peripheral Interface Bus (Up to 100 MHz)100 Mbit/s12.5 MB/s1989
Low Pin Count125 Mbit/s15.63 MB/s [x]2002
STEbus 8-Bit/16 MHz128 Mbit/s16 MB/s1987 (standardized)
C-Bus 16-bit/10 MHz160 Mbit/s20 MB/s[36]1982
HP Precision Bus184 Mbit/s23 MB/s
STD-32 32-bit/8 MHz256 Mbit/s32 MB/s[37]
NESA 32-bit/8 MHz256 Mbit/s32 MB/s[38]
EISA 32-bit/8.33 MHz266.56 Mbit/s33.32 MB/s1988
VME64 32-64bit400 Mbit/s40 MB/s1981
NuBus 10 MHz400 Mbit/s40 MB/s1987 (standardized)
DEC TURBOchannel 32-bit/12.5 MHz400 Mbit/s50 MB/s
MCA 16-32bit/10 MHz660 Mbit/s66 MB/s1987
NuBus90 20 MHz800 Mbit/s80 MB/s1991
APbus 32-bit/25(?) MHz800 Mbit/s100 MB/s[39]
Sbus 32-bit/25 MHz800 Mbit/s100 MB/s1989
DEC TURBOchannel 32-bit/25 MHz800 Mbit/s100 MB/s
Local Bus 98 32-bit/33 MHz1056 Mbit/s132 MB/s[40]
VESA Local Bus (VLB) 32-bit/33 MHz1067 Mbit/s133.33 MB/s1992
PCI 32-bit/33 MHz1067 Mbit/s133.33 MB/s1993
HP GSC-1X1136 Mbit/s142 MB/s
Zorro III 32-bit/async (eq. 37.5 MHz)[41][42]1200 Mbit/s150 MB/s[43]1990
VESA Local Bus (VLB) 32-bit/40 MHz1280 Mbit/s160 MB/s1992
Sbus 64-bit/25 MHz1.6 Gbit/s200 MB/s1995
HP GSC-2X2.048 Gbit/s256 MB/s
PCI 64-bit/33 MHz2.133 Gbit/s266.7 MB/s1993
PCI 32-bit/66 MHz2.133 Gbit/s266.7 MB/s1995
AGP2.133 Gbit/s266.7 MB/s1997
PCI Express 1.0 (×1 link)[44]2.5 Gbit/s250 MB/s [z]2004
RapidIO Gen1 1×2.5 Gbit/s312.5 MB/s
HIO bus2.560 Gbit/s320 MB/s
GIO64 64-bit/40 MHz2.560 Gbit/s320 MB/s
PCI Express 1.0 (×2 link)[44]5 Gbit/s500 MB/s [z]2011
PCI Express 2.0 (×1 link)[45]5 Gbit/s500 MB/s [z]2007
AGP 2×4.266 Gbit/s533.3 MB/s1997
PCI 64-bit/66 MHz4.266 Gbit/s533.3 MB/s
PCI-X DDR 16-bit4.266 Gbit/s533.3 MB/s
RapidIO Gen2 1×5 Gbit/s625 MB/s
PCI 64-bit/100 MHz6.4 Gbit/s800 MB/s
PCI Express 3.0 (×1 link)[46]8 Gbit/s 984.6 MB/s [y]2011
Unified Media Interface (UMI) (×4 link)10 Gbit/s1 GB/s [z]2011
Direct Media Interface (DMI) (×4 link)10 Gbit/s1 GB/s [z]2004
Enterprise Southbridge Interface (ESI)8 Gbit/s1 GB/s
PCI Express 1.0 (×4 link)[44]10 Gbit/s1 GB/s [z]2004
PCI Express 2.0 (x2 link)[44]10 Gbit/s1 GB/s [z]2007
AGP 4×8.533 Gbit/s1.067 GB/s1998
PCI-X 1338.533 Gbit/s1.067 GB/s
PCI-X QDR 16-bit8.533 Gbit/s1.067 GB/s
InfiniBand single 4×[29]8 Gbit/s1 GB/s [z]
RapidIO Gen1 4×10 Gbit/s1.25 GB/s
RapidIO Gen2 2×10 Gbit/s1.25 GB/s
UPA15.360 Gbit/s1.920 GB/s
PCI Express 3.0 (×2 link)[46]16 Gbit/s1.969 GB/s [y]2011
Unified Media Interface 2.0 (UMI 2.0; ×4 link)20 Gbit/s2 GB/s [z]2012
Direct Media Interface 2.0 (DMI 2.0; ×4 link)20 Gbit/s2 GB/s [z]2011
PCI Express 1.0 (×8 link)[44]20 Gbit/s2 GB/s [z]2004
PCI Express 2.0 (×4 link)[45]20 Gbit/s2 GB/s [z]2007
AGP 8×17.066 Gbit/s2.133 GB/s2002
PCI-X DDR17.066 Gbit/s2.133 GB/s
RapidIO Gen2 4×20 Gbit/s2.5 GB/s
Sun JBus (200 MHz)20.48 Gbit/s2.56 GB/s2003
HyperTransport (800 MHz, 16-pair)25.6 Gbit/s3.2 GB/s2001
PCI Express 3.0 (×4 link)[46]32 Gbit/s3.938 GB/s [y]2011
HyperTransport (1 GHz, 16-pair)32 Gbit/s4 GB/s
PCI Express 1.0 (×16 link)[44]40 Gbit/s4 GB/s [z]2004
PCI Express 2.0 (×8 link)[45]40 Gbit/s4 GB/s [z]2007
PCI-X QDR34.133 Gbit/s4.266 GB/s
AGP 8× 64-bit34.133 Gbit/s4.266 GB/s
RapidIO Gen2 8x40 Gbit/s5 GB/s
Direct Media Interface 3.0 (DMI 3.0; ×4 link)40 Gbit/s4 GB/s [z]2015
PCI Express 3.0 (×8 link)[46]64 Gbit/s7.877 GB/s [y]2011
PCI Express 1.0 (×32 link)[44]80 Gbit/s8 GB/s [z]2001
PCI Express 2.0 (×16 link)[45]80 Gbit/s8 GB/s [z]2007
RapidIO Gen2 16x80 Gbit/s10 GB/s
PCI Express 3.0 (×16 link)[46]128 Gbit/s15.75 GB/s [y]2011
CAPI128 Gbit/s15.75 GB/s [y]2014
PCI Express 2.0 (×32 link)[45]160 Gbit/s16 GB/s [z]2007
QPI (4.80GT/s, 2.40 GHz)153.6 Gbit/s19.2 GB/s
HyperTransport 2.0 (1.4 GHz, 32-pair)179.2 Gbit/s22.4 GB/s2004
QPI (5.86GT/s, 2.93 GHz)187.52 Gbit/s23.44 GB/s
QPI (6.40GT/s, 3.20 GHz)204.8 Gbit/s25.6 GB/s
QPI (7.2GT/s, 3.6 GHz)230.4 Gbit/s28.8 GB/s2012
PCI Express 3.0 (×32 link)[46]256 Gbit/s31.51 GB/s [y]2011
PCI Express 4.0 (×16 link)[47]256 Gbit/s31.51 GB/s[y]2018
CAPI 2256 Gbit/s31.51 GB/s[y]2016
QPI (8.0GT/s, 4.0 GHz)256.0 Gbit/s32.0 GB/s2012
QPI (9.6GT/s, 4.8 GHz)307.2 Gbit/s38.4 GB/s2014
HyperTransport 3.0 (2.6 GHz, 32-pair)332.8 Gbit/s41.6 GB/s2006
HyperTransport 3.1 (3.2 GHz, 32-pair)409.6 Gbit/s51.2 GB/s2008
CXL Specification 1.x (×16 link)512 Gbit/s63.02 GB/s2019
PCI Express 5.0 (×16 link)[48]512 Gbit/s63.02 GB/s[y]2019
NVLink 1.0640 Gbit/s80 GB/s2016
NVLink 2.01.2 Tbit/s150 GB/s2017
Infinity Fabric (Max theoretical)4.096 Tbit/s512 GB/s2017

x LPC protocol includes high overhead. While the gross data rate equals 33.3 million 4-bit-transfers per second (or 16.67 MB/s), the fastest transfer, firmware read, results in 15.63 MB/s. The next fastest bus cycle, 32-bit ISA-style DMA write, yields only 6.67 MB/s. Other transfers may be as low as 2 MB/s.[49]

y Uses 128b/130b encoding, meaning that about 1.54% of each transfer is used by the interface instead of carrying data between the hardware components at each end of the interface. For example, a single link PCIe 3.0 interface has an 8 Gbit/s transfer rate, yet its usable bandwidth is only about 7.88 Gbit/s.

z Uses 8b/10b encoding, meaning that 20% of each transfer is used by the interface instead of carrying data from between the hardware components at each end of the interface. For example, a single link PCIe 1.0 has a 2.5 Gbit/s transfer rate, yet its usable bandwidth is only 2 Gbit/s (250 MB/s).


PC Card 16-bit 255 ns byte mode31.36 Mbit/s3.92 MB/s
PC Card 16-bit 255 ns word mode62.72 Mbit/s7.84 MB/s
PC Card 16-bit 100 ns byte mode80 Mbit/s10 MB/s
PC Card 16-bit 100 ns word mode160 Mbit/s20 MB/s
PC Card 32-bit (CardBus) byte mode267 Mbit/s33.33 MB/s
ExpressCard 1.2 USB 2.0 mode480 Mbit/s60 MB/s
PC Card 32-bit (CardBus) word mode533 Mbit/s66.66 MB/s
PC Card 32-bit (CardBus) doubleword mode1067 Mbit/s133.33 MB/s
ExpressCard 1.2 PCI Express mode2500 Mbit/s250 MB/s
ExpressCard 2.0 USB 3.0 mode4800 Mbit/s600 MB/s
ExpressCard 2.0 PCI Express mode5000 Mbit/s625 MB/s


Teletype Model 33 paper tape70 bit/s10 B/s1963
TRS-80 Model 1 Level 1 BASIC cassette tape interface250 bit/s32 B/s1977
Apple 2 cassette tape interface1.5 kbit/s200 B/s1977
Single Density 8-inch FM Floppy Disk Controller (160 KB)250 kbit/s31 KB/s1973
Double Density 5.25-inch MFM Floppy Disk Controller (360 KB)500 kbit/s62 KB/s1978
High Density MFM Floppy Disk Controller (1.2 MB/1.44 MB)1 Mbit/s124 KB/s1984
CD Controller (1×)1.171 Mbit/s0.146 MB/s1988
MFM hard disk5 Mbit/s0.625 MB/s1980
RLL hard disk7.5 Mbit/s0.937 MB/s
DVD Controller (1×)11.1 Mbit/s1.32 MB/s
ESDI24 Mbit/s3 MB/s
ATA PIO Mode 026.4 Mbit/s3.3 MB/s1986
HD DVD Controller (1×)36 Mbit/s4.5 MB/s
Blu-ray Controller (1×)36 Mbit/s4.5 MB/s
SCSI (Narrow SCSI) (5 MHz)[50]40 Mbit/s5 MB/s1986
ATA PIO Mode 141.6 Mbit/s5.2 MB/s1994
ATA PIO Mode 266.4 Mbit/s8.3 MB/s1994
Fast SCSI (8 bits/10 MHz)80 Mbit/s10 MB/s
ATA PIO Mode 388.8 Mbit/s11.1 MB/s1996
AoE over Fast Ethernet[51]100 Mbit/s11.9 MB/s2009
iSCSI over Fast Ethernet[52]100 Mbit/s11.9 MB/s2004
ATA PIO Mode 4133.3 Mbit/s16.7 MB/s1996
Fast Wide SCSI (16 bits/10 MHz)160 Mbit/s20 MB/s
Ultra SCSI (Fast-20 SCSI) (8 bits/20 MHz)160 Mbit/s20 MB/s
SD (High Speed)200 Mbit/s25 MB/s
Ultra DMA ATA 33264 Mbit/s33 MB/s1998
Ultra Wide SCSI (16 bits/20 MHz)320 Mbit/s40 MB/s
Ultra-2 SCSI 40 (Fast-40 SCSI) (8 bits/40 MHz)320 Mbit/s40 MB/s
SDHC/SDXC/SDUC (UHS-I Full Duplex)400 Mbit/s50 MB/s
Ultra DMA ATA 66533.6 Mbit/s66.7 MB/s2000
Blu-ray Controller (16×)576 Mbit/s72 MB/s
Ultra-2 wide SCSI (16 bits/40 MHz)640 Mbit/s80 MB/s
Serial Storage Architecture SSA640 Mbit/s80 MB/s1990
Ultra DMA ATA 100800 Mbit/s100 MB/s2002
Fibre Channel 1GFC (1.0625 GHz)[53]850 Mbit/s103.23 MB/s1997
AoE over gigabit Ethernet, jumbo frames[54]1 Gbit/s124.2 MB/s2009
iSCSI over gigabit Ethernet, jumbo frames[55]1 Gbit/s123.9 MB/s2004
Ultra DMA ATA 1331.064 Gbit/s133 MB/s2005
SDHC/SDXC/SDUC (UHS-II Full Duplex)1.25 Gbit/s156 MB/s
Ultra-3 SCSI (Ultra 160 SCSI; Fast-80 Wide SCSI) (16 bits/40 MHz DDR)1.28 Gbit/s160 MB/s
SATA revision 1.0[56]1.500 Gbit/s150 MB/s [a]2003
Fibre Channel 2GFC (2.125 GHz)[53]1.700 Gbit/s206.5 MB/s2001
Ultra-320 SCSI (Ultra4 SCSI) (16 bits/80 MHz DDR)2.560 Gbit/s320 MB/s
Serial Attached SCSI (SAS) SAS-1[56]3 Gbit/s300 MB/s [a]2004
SATA Revision 2.0[56]3 Gbit/s300 MB/s [a]2004
SDHC/SDXC/SDUC (UHS-III Full Duplex)2.5 Gbit/s312 MB/s
Fibre Channel 4GFC (4.25 GHz)[53]3.4 Gbit/s413 MB/s2004
Serial Attached SCSI (SAS) SAS-2[56]6 Gbit/s600 MB/s [a]2009
SATA Revision 3.0[56]6 Gbit/s600 MB/s [a]2008
Fibre Channel 8GFC (8.50 GHz)[53]6.8 Gbit/s826 MB/s2005
SDHC/SDXC/SDUC (SD Express)7.9 Gbit/s985 MB/s
AoE over 10GbE[54]10 Gbit/s1.242 GB/s2009
iSCSI over 10GbE[55]10 Gbit/s1.239 GB/s2004
FCoE over 10GbE[57]10 Gbit/s1.206 GB/s2009
Serial Attached SCSI (SAS) SAS-3[56]12 Gbit/s1.2 GB/s2013
Fibre Channel 16GFC (14.025 GHz)[53]13.6 Gbit/s1.652 GB/s [b]2011
SATA revision 3.2 - SATA Express16 Gbit/s2 GB/s2013
Serial Attached SCSI (SAS) 422.5 Gbit/s2.4 GB/s [c]2017
UFS (version 3.0)23.2 Gbit/s2.9 GB/s2018
Fibre Channel 32GFC (28.05 GHz)[53]26.424 Gbit/s3.303 GB/s [b]2016
NVMe over M.2 or U.2 (using PCI Express 3.0 ×4 link)[46]32 Gbit/s3.938 GB/s2013
iSCSI over InfiniBand32 Gbit/s4 GB/s2007
iSCSI over 100G Ethernet[55]100 Gbit/s12.392 GB/s2010
FCoE over 100G Ethernet[57]100 Gbit/s12.064 GB/s2010

a Uses 8b/10b encoding b Uses 64b/66b encoding c Uses 128b/150b encoding


Apple Desktop Bus10.0 kbit/s1.25 kB/s1986
PS/2 port12.0 kbit/s1.5 kB/s1987
Serial MIDI31.25 kbit/s3.9 kB/s1983
CBM Bus max[58][59]41.6 kbit/s5.1 kB/s1981
Serial RS-232 max230.4 kbit/s28.8 kB/s1962
Serial DMX512A250.0 kbit/s31.25 kB/s1998
Parallel (Centronics/IEEE 1284)1 Mbit/s125 kB/s1970 (standardized 1994)
Serial 16550 UART max1.5 Mbit/s187.5 kB/s
USB 1.0 low speed1.536 Mbit/s192 kB/s1996
Serial UART max2.7648 Mbit/s345.6 kB/s
GPIB/HPIB (IEEE-488.1) IEEE-488 max.8 Mbit/s1 MB/sLate 1960s (standardized 1976)
Serial EIA-422 max.10 Mbit/s1.25 MB/s
USB 1.0 full speed12 Mbit/s1.5 MB/s1996
Parallel (Centronics/IEEE 1284) EPP (Enhanced Parallel Port)16 Mbit/s2 MB/s1992
Parallel (Centronics/IEEE 1284) ECP (Extended Capability Port)20 Mbit/s2.5 MB/s1994
Serial EIA-485 max.35 Mbit/s4.375 MB/s
GPIB/HPIB (IEEE-488.1-2003) IEEE-488 max.64 Mbit/s8 MB/s
FireWire (IEEE 1394) 10098.304 Mbit/s12.288 MB/s1995
FireWire (IEEE 1394) 200196.608 Mbit/s24.576 MB/s1995
FireWire (IEEE 1394) 400393.216 Mbit/s49.152 MB/s1995
USB 2.0 high speed480 Mbit/s60 MB/s2000
FireWire (IEEE 1394b) 800[60]786.432 Mbit/s98.304 MB/s2002
Fibre Channel 1 Gb SCSI1.0625 Gbit/s100 MB/s
FireWire (IEEE 1394b) 1600[60]1.573 Gbit/s196.6 MB/s2007
Fibre Channel 2 Gb SCSI2.125 Gbit/s200 MB/s
eSATA (SATA 300)3 Gbit/s375 MB/s2004
CoaXPress Base (up and down bidirectional link)3.125 Gbit/s + 20.833 Mbit/s390 MB/s2009
FireWire (IEEE 1394b) 3200[60]3.1457 Gbit/s393.216 MB/s2007
External PCI Express 2.0 ×14 Gbit/s500 MB/s
Fibre Channel 4 Gb SCSI4.25 Gbit/s531.25 MB/s
USB 3.0 SuperSpeed (aka USB 3.1 Gen 1)5 Gbit/s625 MB/s2010
eSATA (SATA 600)6 Gbit/s750 MB/s2011
CoaXPress full (up and down bidirectional link)6.25 Gbit/s + 20.833 Mbit/s781 MB/s2009
External PCI Express 2.0 ×28 Gbit/s1 GB/s
USB 3.1 SuperSpeed+ (aka USB 3.1 Gen 2)10 Gbit/s1.25 GB/s2013
External PCI Express 2.0 ×416 Gbit/s2 GB/s
Thunderbolt2 × 10 Gbit/s2 × 1.25 GB/s2011
USB 3.2 SuperSpeed+[61] (aka USB 3.2 Gen 2×2)20 Gbit/s2.5 GB/s2017
Thunderbolt 220 Gbit/s2.5 GB/s2013
External PCI Express 2.0 ×832 Gbit/s4 GB/s
Thunderbolt 3 two links40 Gbit/s5 GB/s2015
USB 4.0[62]40 Gbit/s5 GB/s2019
External PCI Express 2.0 ×1664 Gbit/s8 GB/s


Media Independent Interface (MII; 4 lanes)100 Mbit/s12.5 MB/s
Reduced MII (RMII; 2 lanes)100 Mbit/s12.5 MB/s
Serial MII (SMII; 1 lane)100 Mbit/s12.5 MB/s
Gigabit MII (GMII; 8 lanes)1.0 Gbit/s125 MB/s
Reduced gigabit/s MII (RGMII; 4 lanes)1.0 Gbit/s125 MB/s
Serial gigabit/s MII (SGMII; 2 lanes)1.25 Gbit/s125 MB/s
Reduced serial gigabit/s MII (RSGMII; 2 lanes)2.5 Gbit/s250 MB/s
Reduced serial gigabit/s MII plus (RSGMII-PLUS; 2 lanes)5.0 Gbit/s500 MB/s
Quad serial gigabit/s MII (QSGMII; 2 lanes)5.0 Gbit/s500 MB/s
10 gigabit/s MII (XGMII; 32 lanes)10.0 Gbit/s1.25 GB/s
XGMII attachment unit interface (XAUI; 4 lanes)10.0 Gbit/s1.25 GB/s
40 gigabit/s MII (XLGMII)40.0 Gbit/s5 GB/s
100 gigabit/s MII (CGMII)100.0 Gbit/s12.5 GB/s2008


10 gigabit/s 16-bit interface (XSBI; 16 lanes)0.995 Gbit/s0.124 GB/s

Dynamic random-access memory

The table below shows values for PC memory module types. These modules usually combine multiple chips on one circuit board. SIMM modules connect to the computer via an 8-bit- or 32-bit-wide interface. RIMM modules used by RDRAM are 16-bit- or 32-bit-wide.[63] DIMM modules connect to the computer via a 64-bit-wide interface. Some other computer architectures use different modules with a different bus width.

In a single-channel configuration, only one module at a time can transfer information to the CPU. In multi-channel configurations, multiple modules can transfer information to the CPU at the same time, in parallel. FPM, EDO, SDR, and RDRAM memory was not commonly installed in a dual-channel configuration. DDR and DDR2 memory is usually installed in single- or dual-channel configuration. DDR3 memory is installed in single-, dual-, tri-, and quad-channel configurations. Bit rates of multi-channel configurations are the product of the module bit-rate (given below) and the number of channels.

Module typeChip typeInternal clock[a]Bus clockBus speed[b]Transfer rate
FPM DRAM45 ns22 MHz22 MHz0.177 GT/s1.416 Gbit/s177 MB/s
EDO DRAM30 ns33 MHz33 MHz0.266 GT/s2.128 Gbit/s266 MB/s
PC-66 SDR SDRAM10/15 ns66 MHz66 MHz0.066 GT/s4.264 Gbit/s533 MB/s
PC-100 SDR SDRAM8 ns100 MHz100 MHz0.100 GT/s6.4 Gbit/s800 MB/s
PC-133 SDR SDRAM7/7.5 ns133 MHz133 MHz0.133 GT/s8.528 Gbit/s1.066 GB/s
RIMM-1200 RDRAMPC60075 MHz300 MHz0.600 GT/s9.6 Gbit/s1.2 GB/s
RIMM-1400 RDRAMPC70087.5 MHz350 MHz0.700 GT/s11.2 Gbit/s1.4 GB/s
RIMM-1600 RDRAMPC800100 MHz400 MHz0.800 GT/s12.8 Gbit/s1.6 GB/s
PC-1600 DDR SDRAMDDR-200100 MHz100 MHz0.200 GT/s12.8 Gbit/s1.6 GB/s
RIMM-2100 RDRAMPC1066133 MHz533 MHz1.066 GT/s17.034 Gbit/s2.133 GB/s
PC-2100 DDR SDRAMDDR-266133 MHz133 MHz0.266 GT/s17.034 Gbit/s2.133 GB/s
RIMM-2400 RDRAMPC1200150 MHz600 MHz1.2 GT/s19.2 Gbit/s2.4 GB/s
PC-2700 DDR SDRAMDDR-333166 MHz166 MHz0.333 GT/s21.336 Gbit/s2.667 GB/s
PC-3200 DDR SDRAMDDR-400200 MHz200 MHz0.400 GT/s25.6 Gbit/s3.2 GB/s
PC2-3200 DDR2 SDRAMDDR2-400100 MHz200 MHz0.400 GT/s25.6 Gbit/s3.2 GB/s
PC-3500 DDR SDRAMDDR-433216 MHz216 MHz0.433 GT/s27.728 Gbit/s3.466 GB/s
PC-3700 DDR SDRAMDDR-466233 MHz233 MHz0.466 GT/s29.864 Gbit/s3.733 GB/s
PC-4000 DDR SDRAMDDR-500250 MHz250 MHz0.500 GT/s32 Gbit/s4 GB/s
PC-4200 DDR SDRAMDDR-533266 MHz266 MHz0.533 GT/s34.128 Gbit/s4.266 GB/s
PC2-4200 DDR2 SDRAMDDR2-533133 MHz266 MHz0.533 GT/s34.128 Gbit/s4.266 GB/s
PC-4400 DDR SDRAMDDR-550275 MHz275 MHz0.550 GT/s35.2 Gbit/s4.4 GB/s
PC-4800 DDR SDRAMDDR-600300 MHz300 MHz0.600 GT/s38.4 Gbit/s4.8 GB/s
PC2-5300 DDR2 SDRAMDDR2-667166 MHz333 MHz0.667 GT/s42.664 Gbit/s5.333 GB/s
PC2-6000 DDR2 SDRAMDDR2-750188 MHz375 MHz0.750 GT/s48 Gbit/s6 GB/s
PC2-6400 DDR2 SDRAMDDR2-800200 MHz400 MHz0.800 GT/s51.2 Gbit/s6.4 GB/s
PC3-6400 DDR3 SDRAMDDR3-800100 MHz400 MHz0.800 GT/s51.2 Gbit/s6.4 GB/s
PC2-7200 DDR2 SDRAMDDR2-900225 MHz450 MHz0.900 GT/s57.6 Gbit/s7.2 GB/s
PC2-8000 DDR2 SDRAMDDR2-1000250 MHz500 MHz1 GT/s64 Gbit/s8 GB/s
PC2-8500 DDR2 SDRAMDDR2-1066266 MHz533 MHz1.066 GT/s68 Gbit/s8.5 GB/s
PC3-8500 DDR3 SDRAMDDR3-1066133 MHz533 MHz1.066 GT/s68 Gbit/s8.5 GB/s
PC2-8800 DDR2 SDRAMDDR2-1100275 MHz550 MHz1.1 GT/s70.4 Gbit/s8.8 GB/s
PC2-9200 DDR2 SDRAMDDR2-1150288 MHz575 MHz1.15 GT/s73.6 Gbit/s9.2 GB/s
PC2-9600 DDR2 SDRAMDDR2-1200300 MHz600 MHz1.2 GT/s76.8 Gbit/s9.6 GB/s
PC2-10000 DDR2 SDRAMDDR2-1250312 MHz625 MHz1.25 GT/s80 Gbit/s10 GB/s
PC3-10600 DDR3 SDRAMDDR3-1333167 MHz667 MHz1.333 GT/s85.336 Gbit/s10.667 GB/s
PC3-11000 DDR3 SDRAMDDR3-1375172 MHz688 MHz1.375 GT/s88 Gbit/s11 GB/s
PC3-12800 DDR3 SDRAMDDR3-1600200 MHz800 MHz1.6 GT/s102.4 Gbit/s12.8 GB/s
PC3-13000 DDR3 SDRAMDDR3-1625203 MHz813 MHz1.625 GT/s104 Gbit/s13 GB/s
PC3-14400 DDR3 SDRAMDDR3-1800225 MHz900 MHz1.8 GT/s115.2 Gbit/s14.4 GB/s
PC3-14900 DDR3 SDRAMDDR3-1866233 MHz933 MHz1.866 GT/s119.464 Gbit/s14.933 GB/s
PC3-16000 DDR3 SDRAMDDR3-2000250 MHz1000 MHz2 GT/s128 Gbit/s16 GB/s
PC3-17000 DDR3 SDRAMDDR3-2133267 MHz1067 MHz2.133 GT/s136.528 Gbit/s17.066 GB/s
PC4-17000 DDR4 SDRAMDDR4-2133267 MHz1067 MHz2.133 GT/s136.5 Gbit/s17 GB/s
PC3-17600 DDR3 SDRAMDDR3-2200275 MHz1100 MHz2.2 GT/s140.8 Gbit/s17.6 GB/s
PC3-19200 DDR3 SDRAMDDR3-2400300 MHz1200 MHz2.4 GT/s153.6 Gbit/s19.2 GB/s
PC4-19200 DDR4 SDRAMDDR4-2400300 MHz1200 MHz2.4 GT/s153.6 Gbit/s19.2 GB/s
PC3-21300 DDR3 SDRAMDDR3-2666333 MHz1333 MHz2.666 GT/s170.5 Gbit/s21.3 GB/s
PC4-21300 DDR4 SDRAMDDR4-2666333 MHz1333 MHz2.666 GT/s170.5 Gbit/s21.3 GB/s
PC3-24000 DDR3 SDRAMDDR3-3000375 MHz1500 MHz3.0 GT/s192 Gbit/s24 GB/s
PC4-24000 DDR4 SDRAMDDR4-3000375 MHz1500 MHz3.0 GT/s192 Gbit/s24 GB/s
PC4-25600 DDR4 SDRAMDDR4-3200400 MHz1600 MHz3.2 GT/s204.8 Gbit/s25.6 GB/s
PC5-41600 DDR5 SDRAMDDR5-5200650 MHz2600 MHz5.2 GT/s332.8 Gbit/s41.6 GB/s
PC5-51200 DDR5 SDRAMDDR5-6400800 MHz3200 MHz6.4 GT/s409.6 Gbit/s51.2 GB/s

a The clock rate at which DRAM memory cells operate. The memory latency is largely determined by this rate. Note that until the introduction of DDR4 the internal clock rate saw relatively slow progress. DDR/DDR2/DDR3 memory uses 2n/4n/8n (respectively) prefetch buffer to provide higher throughput, while the internal memory speed remains similar to that of the previous generation.

b The "memory speed/clock" advertised by manufactures and suppliers usually refers to this rate (with 1 GT/s = 1 GHz). Note that modern types of memory use DDR bus with two transfers per clock.

Graphics processing units' RAM

RAM memory modules are also utilised by graphics processing units; however, memory modules for those differ somewhat from standard computer memory, particularly with lower power requirements, and are specialised to serve GPUs: for example, GDDR3 was fundamentally based on DDR2. Every graphics memory chip is directly connected to the GPU (point-to-point). The total GPU memory bus width varies with the number of memory chips and the number of lanes per chip. For example, GDDR5 specifies either 16 or 32 lanes per "device" (chip), while GDDR5X specifies 64 lanes per chip. Over the years, bus widths rose from 64-bit to 512-bit and beyond: e.g. HBM is 1024 bits wide.[64] Because of this variability, graphics memory speeds are sometimes compared per pin. For direct comparison to the values for 64-bit modules shown above, video RAM is compared here in 64-lane lots, corresponding to two chips for those devices with 32-bit widths. In 2012, high-end GPUs used 8 or even 12 chips with 32 lanes each, for a total memory bus width of 256 or 384 bits. Combined with a transfer rate per pin of 5 GT/s or more, such cards could reach 240 GB/s or more.

RAM frequencies used for a given chip technology vary greatly. Where single values are given below, they are examples from high-end cards.[65] Since many cards have more than one pair of chips, the total bandwidth is correspondingly higher. For example, high-end cards often have eight chips, each 32 bits wide, so the total bandwidth for such cards is four times the value given below.

Module typeChip typeMemory clockTransfers/sTransfer rate
64 lanesDDR350 MHz0.7 GT/s44.8 Gbit/s5.6 GB/s
64 lanesDDR2250 MHz1 GT/s64 Gbit/s8 GB/s
64 lanesGDDR3625 MHz2.5 GT/s159 Gbit/s19.9 GB/s
64 lanesGDDR4275 MHz2.2 GT/s140.8 Gbit/s17.6 GB/s
64 lanesGDDR5[66]625–1000 MHz5–8 GT/s320–512 Gbit/s40–64 GB/s
64 lanesGDDR5X[67]625–875 MHz10–12 GT/s640–896 Gbit/s80–112 GB/s
64 lanes GDDR6 875–1000 MHz 14–16 GT/s 896–1024 Gbit/s 112–128 GB/s
1024 lanes (8 channels @ 128 lanes ea)HBM[68]500 MHz1 GT/s1024 Gbit/s128 GB/s
1024 lanes (8 channels @ 128 lanes ea)HBM2[68][69]500 MHz2 GT/s2048 Gbit/s256 GB/s
1024 lanes (8 channels @ 128 lanes ea)HBM3[69]500 MHz4 GT/s4096 Gbit/s512 GB/s
128 lanes (8 links @ 16 lanes ea)HMC(internal)10 GT/s2560 Gbit/s320 GB/s
64 lanes (4 links @ 16 lanes ea)HMC2(internal)30 GT/s3840 Gbit/s480 GB/s

Digital audio

CD Audio (16-bit PCM)1.411 Mbit/s176.4 kB/s
I²S2.250 Mbit/s @ 24bit/48 kHz0.281 MB/s
AES/EBU2.625 Mbit/s @ 24-bit/48 kHz0.328 MB/s
S/PDIF fs 48kHz3.072 Mbit/s0.384 MB/s
ADAT Lightpipe (Type I)9.216 Mbit/s1.152 MB/s
AC'9712.288 Mbit/s1.536 MB/s
HDMI36.864 Mbit/s4.608 MB/s
DisplayPort36.864 Mbit/s4.608 MB/s
Intel High Definition Audio rev. 1.0[70]48 Mbit/s outbound; 24 Mbit/s inbound6 MB/s outbound; 3 MB/s inbound
MADI100 Mbit/s12.5 MB/s

Digital video interconnects

Data rates given are from the video source (e.g., video card) to receiving device (e.g., monitor) only. Out of band and reverse signaling channels are not included.

HD-SDI (SMPTE 292M)1.485 Gbit/s0.186 GB/s
Camera Link Base (single) 24-bit 85 MHz2.040 Gbit/s0.255 GB/s
LVDS Display Interface[71]2.80 Gbit/s0.35 GB/s
3G-SDI (SMPTE 424M)2.97 Gbit/s0.371 GB/s2006
Single link DVI4.95 Gbit/s0.619 GB/s [a]1999
HDMI 1.0[72]4.95 Gbit/s0.619 GB/s [a]2002
Camera Link full (dual) 64-bit 85 MHz5.44 Gbit/s0.680 GB/s
6G-SDI (SMPTE 2081)5.94 Gbit/s0.75 GB/s2015
DisplayPort 1.0 (4-lane Reduced Bit Rate)[73]6.48 Gbit/s0.810 GB/s [a]2006
Dual link DVI9.90 Gbit/s1.238 GB/s [a]1999
Thunderbolt2 × 10 Gbit/s2 × 1.25 GB/s2011
HDMI 1.3[74]10.2 Gbit/s1.275 GB/s [a]2006
Dual High-Speed LVDS Display Interface10.5 Gbit/s1.312 GB/s
DisplayPort 1.0 (4-lane High Bit Rate)[73]10.8 Gbit/s1.35 GB/s [a]2006
12G-SDI (SMPTE 2082)11.88 Gbit/s1.5 GB/s2015
HDMI 2.0[75]18.0 Gbit/s2.25 GB/s [a]2013
Thunderbolt 220 Gbit/s2.5 GB/s2013
DisplayPort 1.2 (4-lane High Bit Rate 2)[73]21.6 Gbit/s2.7 GB/s [a]2009
DisplayPort 1.3 (4-lane High Bit Rate 3)32.4 Gbit/s4.05 GB/s [a]2014 (2016)
superMHL36 Gbit/s4.5 GB/s2015
Thunderbolt 340 Gbit/s5 GB/s2015
HDMI 2.1[76]48 Gbit/s6 GB/s [b]2017
DisplayPort 2.0 (4-lane)80 Gbit/s10 GB/s [c]2019

a Uses 8b/10b encoding (20% coding overhead) b Uses 16b/18b encoding (11% overhead) c Uses 128b/132b encoding (3% overhead)

See also


  1. NIST-Enhanced-WWVB-Broadcast-Format-sept-2012-Radio-Station-staff, By John Lowe, September 2012,
  2. Archived version
  3. TTY uses a Baudot code, not ASCII. This uses 5 bits per character instead of 8, plus one start and approx. 1.5 stop bits (7.5 total bits per character sent).
  4. Morse can transport 26 alphabetic, 10 numeric and one interword gap plaintext symbols. Transmitting 37 different symbols requires 5.21 bits of information (25.21=37). A skilled operator encoding the benchmark "PARIS" plus an interword gap (equal to 31.26 bits) at 40 wpm is operating at an equivalence of 20.84 bit/s.
  5. WPM, or Words Per Minute, is the number of times the word "PARIS" is transferred per minute. Strictly speaking the code is quinary, accounting inter-element, inter-letter, and inter-word gaps, yielding 50 binary elements (bits) per one word. Counting characters, including inter-word gaps, gives six characters per word or 240 characters per minute, and finally four characters per second.
  6. All modems are wrongly assumed to be in serial operation with 1 start bit, 8 data bits, no parity, and 1 stop bit (2 stop bits for 110-baud modems). Therefore, currently modems are wrongly calculated with transmission of 10 bits per 8-bit byte (11 bits for 110-baud modems). Although the serial port is nearly always used to connect a modem and has equivalent data rates, the protocols, modulations and error correction differ completely.
  7. Modem Types and Timeline, Daxal Communications, 2003-12-16, archived from the original on 2008-10-08, retrieved 2009-04-16
  8. "ITU-T Recommendations: V Series: Data communication over the telephone network". ITU.
  9. 56K modems: V.90 and V.92 have just 5% overhead for the protocol signalling. The maximum capacity can only be achieved when the upstream (service provider) end of the connection is digital, i.e. a DS0 channel.
  10. Note that effective aggregate bandwidth for an ISDN installation is typically higher than the rates shown for a single channel due to the use of multiple channels. A basic rate interface (BRI) provides two "B" channels and one "D" channel. Each B channel provides 64 kBit/s bandwidth and the "D" channel carries signaling (call setup) information. B channels can be bonded to provide a 128 kbit/s data rate. Primary rate interfaces (PRI) vary depending on whether the region uses E1 (Europe, world) or T1 (North America) bearers. In E1 regions, the PRI carries 30 B-channels and one D-channel; in T1 regions the PRI carries 23 B-channels and one D-channel. The D-channel has different bandwidth on the two interfaces.
  11. Massey, David (2006-07-04), "Timeline of Telecommunications", Telephone Tribute, retrieved 2009-04-16
  13. "Recommendation G.991.1 (10/98)". ITU.
  14. DOCSIS 1.0 Archived 2006-06-13 at the Wayback Machine includes technology which first became available around 1995–1996, and has since become very widely deployed. DOCSIS 1.1 Archived 2006-06-13 at the Wayback Machine introduces some security improvements and Quality of Service (QoS).
  15. DOCSIS 2.0 Archived 2009-09-04 at the Wayback Machine specifications provide increased upstream throughput for symmetric services.
  16. "G.983.2". ITU.
  17. DOCSIS 3.0 Archived 2006-06-19 at the Wayback Machine includes support for channel bonding and IPv6.
  18. "G.984.4 : Gigabit-capable passive optical networks (G-PON)". ITU.
  19. DOCSIS 3.1 is currently in development by the Cablelabs Consortium
  20. "G.987 : 10-Gigabit-capable passive optical network (XG-PON) systems". ITU.
  21. "G.989 : 40-Gigabit-capable passive optical networks (NG-PON2)". ITU.
  22. Most operators only support up to 9600bit/s
  23. SDSL is available in various speeds.
  24. ADSL connections will vary in throughput from 64 kbit/s to several Mbit/s depending on configuration. Most are commonly below 2 Mbit/s. Some ADSL and SDSL connections have a higher digital bandwidth than T1 but their rate is not guaranteed, and will drop when the system gets overloaded, whereas the T1 type connections are usually guaranteed and have no contention ratios.
  25. Satellite internet may have a high bandwidth but also has a high latency due to the distance between the modem, satellite and hub. One-way satellite connections exist where all the downstream traffic is handled by satellite and the upstream traffic by land-based connections such as 56K modems and ISDN.
  26. "MoCA 1.1 improves throughput" over coaxial cable to 175 Mbits/s versus the 100 Mbits/s provided by the MoCA 1.0 specification.
  27. FireWire natively supports TCP/IP, and is often used at an alternative to Ethernet when connecting 2 nodes.
  28. Data rate comparison between FW and Giganet shows that FW's lower overhead has nearly the same throughput as Giganet. Archived 2008-02-07 at the Wayback Machine
  29. InfiniBand SDR, DDR and QDR use an 8b/10b encoding scheme.
  30. InfiniBand FDR-10, FDR and EDR use a 64b/66b encoding scheme.
  31. Lee, Bill. "Chair of marketing working group". IBTA Blog. IBTA. Archived from the original on 2018-06-25. Retrieved 25 June 2018.
  32. Mac History
  33. VAW: Apple IIgs Specs Archived 2011-01-10 at the Wayback Machine
  34. "After 35 years of I2C, I3C Improves Capability and Performance | Sensors and MEMS". Retrieved 2019-06-26.
  35. The Zorro II bus use 4 clocks per 16-Bit of data transferred. See the Zorro III technical specification for more information.
  36. Japan wikipedia article, Bus used in early NEC PC-9800 series and compatible systems
  37. STD 32 Bus Specification and Designer's Guide
  38. Japan wikipedia article, Bus used in later NEC PC-9800 series and compatible systems
  39. Local Area Networks Newsletter by Paul Polishuk, September 1992, Page 7 (APbus used in Sony NeWS and NEC UP4800 workstations and NEC EWS4800 servers after VMEbus and before switch to PCI)
  40. Japan wikipedia article, Bus used in NEC PC-9821 series
  41. Dave Haynie, designer of the Zorro III bus, claims in this posting that the theoretical max of the Zorro III bus can be derived by the timing information given in chapter 5 of the Zorro III technical specification.
  42. Dave Haynie, designer of the Zorro III bus, states in this posting that Zorro III is an asynchronous bus and therefore does not have a classical MHz rating. A maximum theoretical MHz value may be derived by examining timing constraints detailed in the Zorro III technical specification, which should yield about 37.5 MHz. No existing implementation performs to this level.
  43. Dave Haynie, designer of the Zorro III bus, claims in this posting that Zorro III has a max burst rate of 150 MB/s.
  44. Note that PCI Express 1.0/2.0 lanes use an 8b/10b encoding scheme.
  45. PCIe 2.0 effectively doubles the bus standard's bandwidth from 2.5 GT/s to 5 GT/s
  46. PCIe 3.0 increases the bandwidth from 5 GT/s to 8 GT/s and switches to 128b-130b encoding
  47. Born, Eric (8 June 2017). "PCIe 4.0 specification finally out with 16 GT/s on tap". Tech Report. Retrieved 21 February 2018.
  48. Smith, Ryan. "PCI-SIG Finalizes PCIe 5.0 Specification: x16 Slots to Reach 64GB/sec". Retrieved 2019-06-26.
  49. Intel LPC Interface Specification 1.1
  50. SCSI-1, SCSI-2 and SCSI-3 are signaling protocols and do not explicitly refer to a specific rate. Narrow SCSI exists using SCSI-1 and SCSI-2. Higher rates use SCSI-2 or later.
  51. minimum overhead is 38 byte L1/L2, 14 byte AoE per 1024 byte user data
  52. minimum overhead is 38 byte L1/L2, 20 byte IP, 20 byte TCP per 1460 byte user data
  53. Fibre Channel 1GFC, 2GFC, 4GFC use an 8b/10b encoding scheme. Fibre Channel 10GFC, which uses a 64B/66B encoding scheme, is not compatible with 1GFC, 2GFC and 4GFC, and is used only to interconnect switches.
  54. minimum overhead is 38 byte L1/L2, 14 byte AoE per 8192 byte user data
  55. minimum overhead is 38 byte L1/L2, 20 byte IP, 20 byte TCP per 8960 byte user data
  56. SATA and SAS use an 8b/10b encoding scheme.
  57. minimum overhead is 38 byte L1/L2, 36 byte FC per 2048 byte user data
  58. proprietary serial version of IEEE-488 by Commodore International
  60. FireWire (IEEE 1394b) uses an 8b/10b encoding scheme.
  61. Dent, Steve (26 July 2017). "USB 3.2 doubles your connection speeds with the same port". Engadget. Retrieved 26 July 2017.
  62. Shilov, Anton. "USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB". Retrieved 2019-06-26.
  63. "RDRAM Memory Architecture".
  64. Comparison of AMD graphics processing units
  65. Comparison of Nvidia graphics processing units
  66. "GRAPHICS DOUBLE DATA RATE (GDDR5) SGRAM STANDARD JESD212C". JEDEC. 2016-02-01. Retrieved 2016-08-10.
  67. "GRAPHICS DOUBLE DATA RATE (GDDR5X) SGRAM STANDARD JESD232". JEDEC. 2015-11-01. Retrieved 2016-08-10.
  68. Shilov, Anton (20 January 2016). "JEDEC Publishes HBM2 Specification". Anandtech. Retrieved 16 May 2017.
  69. Walton, Mark (23 August 2016). "HBM3: Cheaper, up to 64GB on-package, and terabytes-per-second bandwidth". Ars Technica. Retrieved 3 February 2017.
  70. High Definition Audio Specification, Revision 1.0a, 2010
  71., Panel display interfaces and bandwidth: From TTL, LVDS, TDMS to DisplayPort
  72. "". Archived from the original on 2008-12-05. Retrieved 2008-10-20.
  73. Displayport Technical Overview Archived 2011-07-26 at the Wayback Machine, May 2010
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