List of device bandwidths

From Wikipedia, the free encyclopedia

This is a list of device bandwidths: the channel capacity (or, more informally, bandwidth) of some computer devices employing methods of data transport is listed by bit/s, kilobit/s (kbit/s), megabit/s (Mbit/s), or gigabit/s (Gbit/s) as appropriate and also MB/s or megabytes per second. They are listed in order from lowest bandwidth to highest.

Whether to use bit/s or byte/s (B/s) is a matter of debate. The most commonly cited measurement is bolded. In general, parallel interfaces are quoted in byte/s (B/s), serial in bit/s.

Many of these figures are theoretical maxima, and various real-world considerations will generally keep the actual effective throughput much lower. See Measuring network throughput. The actual throughput achievable on Ethernet networks, for example (especially when heavily loaded), is a subject of hot debate.


Contents


Note: All of the bandwidth values listed in this article are true metric quantities, i.e. a kilobit = 1000 bits, NOT 1024 bits; also, a kilobyte = 1000 bytes.[1]


CONNECTION BITS BYTES

[edit] TTY/Teleprinter or Telecommunications device for the deaf
TTY (V.18) 45 bit/s 6 cps
TTY (V.18) 50 bit/s 6.71 cps
Note: [2]

[edit] Modems
Modem 110 baud 110 bit/s 10 B/s
Modem 300 baud (V.21) 300 bit/s 30 B/s
Modem Bell 103 (Bell 103) 300 bit/s 30 B/s
Modem 1200 (V.22) 1 200 bit/s 120 B/s
Modem Bell 212A (Bell 212A) 1 200 bit/s 120 B/s
Modem 2400 (V.22bis) 2 400 bit/s 240 B/s
Modem 9600 (V.32) 9 600 bit/s 960 B/s
Modem 14.4k (V.32bis) 14.4 kbit/s 1.44 kB/s
Modem 19.2k (V.32terbo) 19.2 kbit/s 1.92 kB/s
Modem 28.8k (V.34) 28.8 kbit/s 2.88 kB/s
Modem 33.6k (V.34plus/V.34bis) 33.6 kbit/s 3.36 kB/s
Modem 56k[3] (V.90) (upstream) 33.6 kbit/s 3.36 kB/s
Modem 56k[3] (V.90) (downstream) 56 kbit/s 5.6 kB/s
Modem 56k[3] (V.92) (upstream) 48 kbit/s 4.8 kB/s
Modem 56k[3] (V.92) (downstream) 56 kbit/s 5.6 kB/s
Note: [4]

[edit] ISDN
ISDN Basic Rate Interface (BRI) data channel (B-channel) 64 kbit/s 8 kB/s
ISDN Basic Rate Interface (BRI) signalling channel (D-channel) 16 kbit/s 2 kB/s
ISDN Primary Rate Interface (PRI) data channel (B-channel) 64 kbit/s 8 kB/s
ISDN Primary Rate Interface (PRI) signalling channel (D-channel) 64 kbit/s 8 kB/s
Note that [5].

[edit] Computer buses
ISA 8-Bit/4.77 MHz 38.18 Mbit/s 4.77 MB/s
ISA 16-Bit/8.33 MHz 133.33 Mbit/s 16.67 MB/s
Low Pin Count 133.33 Mbit/s 16.67 MB/s
HP-Precision Bus 23 MB/s
EISA 8-16-32bits/8.33 MHz 320 Mbit/s 32 MB/s
VME64 32-64bits 400 Mbit/s 40 MB/s
NuBus 10MHz 400 Mbit/s 40 MB/s
DEC TURBOchannel 32-bit/12.5 MHz 400 Mbit/s 50 MB/s
MCA 16-32bits/10 MHz 660 Mbit/s 66 MB/s
NuBus90 20MHz 800 Mbit/s 80 MB/s
Sbus 32-bit/25 MHz 800 Mbit/s 100 MB/s
DEC TURBOchannel 32-bit/25 MHz 800 Mbit/s 100 MB/s
PCI 32-bit/33 MHz 1.06666 Gbit/s 133.33 MB/s
HP GSC-1X 142 MB/s
Sbus 64-bit/25 MHz 1.6 Gbit/s 200 MB/s
PCI Express (x1 link)[6] 2.5 Gbit/s 250 MB/s
HP GSC-2X 256 MB/s
PCI 64-bit/33 MHz 2.13333 Gbit/s 266.66 MB/s
PCI 32-bit/66 MHz 2.13333 Gbit/s 266.66 MB/s
AGP 1x 2.13333 Gbit/s 266.66 MB/s
AGP 2x 4.26666 Gbit/s 533.33 MB/s
PCI 64-bit/66 MHz 4.26666 Gbit/s 533.33 MB/s
PCI-X DDR 16-bit 4.26666 Gbit/s 533.33 MB/s
PCI 64-bit/100 MHz 6.39999 Gbit/s 799.99 MB/s
AGP 4x 8.53333 Gbit/s 1.06666 GB/s
PCI-X 133 8.53333 Gbit/s 1.06666 GB/s
PCI-X QDR 16-bit 8.53333 Gbit/s 1.06666 GB/s
InfiniBand single 4X 10 Gbit/s 1.25 GB/s
PCI Express (x4 link)[6] 10 Gbit/s 1.25 GB/s
UPA 1.92 GB/s
PCI Express (x8 link)[6] 20 Gbit/s 2 GB/s
AGP 8x 17.066 Gbit/s 2.133 GB/s
PCI-X DDR 17.066 Gbit/s 2.133 GB/s
PCI Express (x16 link)[6] 40 Gbit/s 4 GB/s
PCI-X QDR 34.133 Gbit/s 4.266 GB/s
HyperTransport (800 MHz, 16-pair) 51.2 Gbit/s 6.4 GB/s
HyperTransport (1 GHz, 16-pair) 64 Gbit/s 8 GB/s
PCI Express 2.0 (x32 link)[6] 80 Gbit/s 8 GB/s
HyperTransport (2.6 GHz, 32-pair) 166.4 Gbit/s 20.8 GB/s

[edit] Computer buses (storage)
PIO Mode 0 26.4 Mbit/s 3.3 MB/s
SCSI 1 40 Mbit/s 5 MB/s
PIO Mode 1 41.6 Mbit/s 5.2 MB/s
PIO Mode 2 66.4 Mbit/s 8.3 MB/s
Fast SCSI 2 80 Mbit/s 10 MB/s
PIO Mode 3 88.8 Mbit/s 11.1 MB/s
PIO Mode 4 133.3 Mbit/s 16.7 MB/s
Fast Wide SCSI 2 160 Mbit/s 20 MB/s
Ultra DMA ATA 33 264 Mbit/s 33 MB/s
Ultra Wide SCSI 40 320 Mbit/s 40 MB/s
Ultra DMA ATA 66 528 Mbit/s 66 MB/s
Ultra-2 SCSI 80 640 Mbit/s 80 MB/s
Serial Storage Architecture SSA 640 Mbit/s 80 MB/s
Ultra DMA ATA 100 800 Mbit/s 100 MB/s
Fibre Channel 1GFC (1.0625 GHz) 850 Mbit/s 106.25 MB/s
Ultra DMA ATA 133 1.064 Gbit/s 133 MB/s
Serial ATA (SATA-150) 1.2 Gbit/s 150 MB/s
Ultra-3 SCSI 160 1.28 Gbit/s 160 MB/s
Fibre Channel 2GFC (2.125 GHz) 1.7 Gbit/s 212.5 MB/s
Serial ATA (SATA-300) 2.4 Gbit/s 300 MB/s
Serial Attached SCSI 3 Gbit/s 300 MB/s
Ultra-320 SCSI 2.56 Gbit/s 320 MB/s
Fibre Channel 4GFC (4.25 GHz) 3.4 Gbit/s 425 MB/s
Serial Attached SCSI 2 6 Gbit/s 600 MB/s
Ultra-640 SCSI 5.12 Gbit/s 640 MB/s
Note that [7], [8] and [9]

[edit] Computer buses (external)
Serial RS-232 commonly 9.6 kbit/s 1.2 kB/s
MIDI 31.25 kbit/s 3.9 kB/s
Apple Desktop Bus 125 kbit/s 15.6 kB/s
Serial RS-232 max 230.4 kbit/s 28.8 kB/s
USB Low Speed (USB 1.0) 1.536 Mbit/s 192 kB/s
Parallel (Centronics) 8 Mbit/s 1 MB/s
Serial RS-422 max 10 Mbit/s 1.25 MB/s
USB Full Speed (USB 1.1) 12 Mbit/s 1.5 MB/s
FireWire (IEEE 1394) 100 98.304 Mbit/s 12.288 MB/s
FireWire (IEEE 1394) 200 196.608 Mbit/s 24.576 MB/s
FireWire (IEEE 1394) 400 393.216 Mbit/s 49.152 MB/s
USB Hi-Speed (USB 2.0) 480 Mbit/s 60 MB/s
FireWire (IEEE 1394b) 800 786.432 Mbit/s 98.304 MB/s
FireWire (IEEE 1394b) 1600 1.572864 Gbit/s 196.608 MB/s
Cameralink base 24bit 85MHz 2.04 Gbit/s 261.12 MB/s
External SATA 2.4 Gbit/s 300 MB/s
FireWire (IEEE 1394b) 3200 3.145728 Gbit/s 393.216 MB/s
Note that [10] and [11].

[edit] Wireless device connection
IrDA-Control 72 kbit/s 9 kB/s
IrDA-SIR 115.2 kbit/s 14 kB/s
802.15.4 (2.4 GHz) 250 kbit/s 31.25 kB/s
Bluetooth 1.1 1 Mbit/s 125 kB/s
Bluetooth 2.0+EDR 3 Mbit/s 375 kB/s
IrDA-FIR 4 Mbit/s 0.5 MB/s
IrDA-VFIR 16 Mbit/s 2 MB/s

[edit] Wireless networking
802.11 legacy 0.125 2 Mbit/s 0.25 MB/s
RONJA free source optical wireless 10 Mbit/s 1.25 MB/s
802.11b DSSS 0.125 11 Mbit/s 1.375 MB/s
802.11b+ non-standard DSSS 0.125 44 Mbit/s 5.5 MB/s
802.11a 0.75 54 Mbit/s 6.75 MB/s
802.11g DSSS 0.125 54 Mbit/s 6.75 MB/s
802.11n 540 Mbit/s 67.5 MB/s

[edit] Mobile telephone interfaces
WiDEN '
GSM CSD 2.4 to 14.4 kbit/s 0.3 to 1.8 kB/s
HSCSD upstream 14.4 kbit/s 1.8 kB/s
HSCSD downstream 43.2 kbit/s 5.4 kB/s
GPRS upstream 28.8 kbit/s 3.6 kB/s
GPRS downstream 57.6 kbit/s 7.2 kB/s
EDGE downstream 236.8 kbit/s 29.6 kB/s
UMTS downstream 1920 kbit/s 240 kB/s
HSDPA downstream 1.8 Mbit/s to 14.4 Mbit/s 225 kB/s to 1.8 MB/s
HSUPA downstream '
HSOPA downstream '
CDMA2000 1xRTT downstream '
CDMA2000 1xRTT upstream '
1xEV-DO Rev. 0 downstream 2.4576 Mbit/s
1xEV-DO Rev. 0 upstream 0.15 Mbit/s
1xEV-DO Rev. A downstream 3.1 Mbit/s 396.8 kB/s
1xEV-DO Rev. A upstream 1.8 Mbit/s 230.4 kB/s
1xEV-DO Rev. B downstream 73.5 Mbit/s
1xEV-DO Rev. B upstream '
1xEV-DO Rev. C downstream 280 Mbit/s
1xEV-DO Rev. C upstream '

[edit] Wide area network
DS0 64 kbit/s 8 kB/s
Satellite Internet upstream 64 kbit/s to 1 Mbit/s 8 kB/s to 128 kB/s
Satellite Internet downstream 128 kbit/s to 16 Mbit/s 16 kB/s to 2 MB/s
Frame Relay 8 kbit/s to 45 Mbit/s 1 kB/s to 5.625 MB/s
G.SHDSL 2.304 Mbit/s 0.288 MB/s
SDSL 64 kbit/s to 4.608 Mbit/s 8 kB/s to 576 kB/s
G.Lite (aka ADSL Lite) upstream 512 kbit/s 64 kB/s
G.Lite (aka ADSL Lite) downstream 1.5 Mbit/s 192 kB/s
ADSL upstream 64 kbit/s to 1.024 Mbit/s 8 kB/s to 128 kB/s
ADSL downstream 256 kbit/s to 8 Mbit/s 32 kB/s to 1 MB/s
ADSL2 upstream 64 kbit/s to 3.5 Mbit/s 8 kB/s to 448 kB/s
ADSL2 downstream 256 kbit/s to 12 Mbit/s 32 kB/s to 1.5 MB/s
ADSL2Plus upstream 64 kbit/s to 3.5 Mbit/s 8 kB/s to 448 kB/s
ADSL2Plus downstream 256 kbit/s to 24 Mbit/s 32 kB/s to 3 MB/s
DOCSIS v1.0 (Cable Modem) upstream 10 Mbit/s 1.25 MB/s
DOCSIS v1.0 (Cable Modem) downstream 38 Mbit/s 4.75 MB/s
DOCSIS v2.0 (Cable Modem) upstream 30 Mbit/s 12.5 MB/s
DOCSIS v2.0 (Cable Modem) downstream 40 Mbit/s 5 MB/s
DOCSIS v3.0 (Cable Modem) upstream 160 Mbit/s 20 MB/s
DOCSIS v3.0 (Cable Modem) downstream 120 Mbit/s 15 MB/s
DS1/T1 1.544 Mbit/s 192.5 kB/s
E1 2.048 Mbit/s 256 kB/s
T2 6.312 Mbit/s 789 KB/s
E2 8.448 Mbit/s 1.056 MB/s
E3 34.368 Mbit/s 4.296 MB/s
DS3/T3 ('45 Meg') 44.736 Mbit/s 5.5925 MB/s
STS-1/EC-1/OC-1/STM-0 51.84 Mbit/s 6.48 MB/s
VDSL (symmetry optional) 12 Mbit/s to 100 Mbit/s 1.5 MB/s to 12.5 MB/s
VDSL2 (symmetry optional) 12 Mbit/s to 250 Mbit/s 1.5 MB/s to 31.25 MB/s
LR-VDSL2 (4 to 5 km [long-]range) (symmetry optional) 1 Mbit/s to 4 Mbit/s 128 kB/s to 512 kB/s
OC-1 51.84 Mbit/s 6.48 MB/s
OC-3/STM-1 155.52 Mbit/s 19.44 MB/s
T4 274.176 Mbit/s 34.272 MB/s
T5 400.352 Mbit/s 50.044 MB/s
OC-9 466.56 Mbit/s 58.32 MB/s
OC-12/STM-4 622.08 Mbit/s 77.76 MB/s
OC-18 933.12 Mbit/s 116.64 MB/s
OC-24 1.244 Gbit/s 155.5 MB/s
OC-36 1.9 Gbit/s 237.5 MB/s
OC-48/STM-16 2.48832 Gbit/s 311.04 MB/s
OC-96 4.976 Gbit/s 622 MB/s
OC-192/STM-64 9.95328 Gbit/s 1.24416 GB/s
10 Gigabit Ethernet WAN PHY 9.95328 Gbit/s 1.24416 GB/s
10 Gigabit Ethernet LAN PHY 10 Gbit/s 1.25 GB/s
OC-256 13.271 Gbit/s 1.65888 GB/s
OC-768/STM-256 39.81312 Gbit/s 4.97664 GB/s
OC-1536/STM-512 79.626 Gbit/s 9.95325 GB/s
OC-3072/STM-1024 159.252 Gbit/s 19.9065 GB/s

[edit] Local area network
LocalTalk 230.1 kbit/s 28.8 kB/s
Econet 800 kbit/s 100 kB/s
ARCNET (Standard) 2.5 Mbit/s 0.3125 MB/s
Token Ring (Original) 4.16 Mbit/s 0.52 MB/s
Ethernet (10base-X) 10 Mbit/s 1.25 MB/s
Token Ring (Later) 16 Mbit/s 2 MB/s
Fast Ethernet (100base-X) 100 Mbit/s 12.5 MB/s
FDDI 100 Mbit/s 12.5 MB/s
Gigabit Ethernet (1000base-X) 1 Gbit/s 125 MB/s
Myrinet 2000 2 Gbit/s 250 MB/s
Infiniband 1X 2.5 Gbit/s 312 MB/s
10 gigabit Ethernet (10Gbase-X) 10 Gbit/s 1.25 GB/s
Myri 10G 10 Gbit/s 1.25 GB/s
Infiniband 4X 10 Gbit/s 1.25 GB/s
Scalable Coherent Interconnect (SCI) Dual Channel SCI, x8 PCIe 20 Gbit/s 2.5 GB/s
Infiniband 12X 30 Gbit/s 3.75 GB/s

[edit] Memory Interconnect Buses / RAM
SPARC MBus 2.56 Gbit/s 0.32 GB/s
PC66 SDRAM 4.264 Gbit/s 0.533 GB/s
PC100 SDRAM 6.4 Gbit/s 0.8 GB/s
HP Runway bus 125MHz 64-bit 6.4 Gbit/s 0.8 GB/s
PC133 SDRAM 8.528 Gbit/s 1.066 GB/s
PC800 RDRAM (single-channel) 12.8 Gbit/s 1.6 GB/s
PC1600 DDR-SDRAM (single channel) 12.8 Gbit/s 1.6 GB/s
HP Runway bus 125MHz 64-bit DDR 16 Gbit/s 2 GB/s
PC1066 RDRAM (single-channel) 16.8 Gbit/s 2.1 GB/s
PC2100 DDR-SDRAM (single channel) 16.8 Gbit/s 2.1 GB/s
PC1200 RDRAM (single-channel) 19.2 Gbit/s 2.4 GB/s
PC2700 DDR-SDRAM (single channel) 21.6 Gbit/s 2.7 GB/s
PC800 RDRAM (dual-channel) 25.6 Gbit/s 3.2 GB/s
PC1600 DDR-SDRAM (dual channel) 25.6 Gbit/s 3.2 GB/s
PC3200 DDR-SDRAM (single channel) 25.6 Gbit/s 3.2 GB/s
PC2-3200 DDR2-SDRAM (single channel) 25.6 Gbit/s 3.2 GB/s
PC1066 RDRAM (dual-channel) 33.6 Gbit/s 4.2 GB/s
PC2100 DDR-SDRAM (dual channel) 33.6 Gbit/s 4.2 GB/s
PC2-4200 DDR2-SDRAM (single channel) 34.136 Gbit/s 4.267 GB/s
PC4000 DDR-SDRAM (single channel) 34.3 Gbit/s 4.287 GB/s
PC1200 RDRAM (dual-channel) 38.4 Gbit/s 4.8 GB/s
PC2-5400 DDR2-SDRAM (single channel) 42.664 Gbit/s 5.333 GB/s
PC2700 DDR-SDRAM (dual channel) 43.2 Gbit/s 5.4 GB/s
PC3200 DDR-SDRAM (dual channel) 51.2 Gbit/s 6.4 GB/s
PC2-3200 DDR2-SDRAM (dual channel) 51.2 Gbit/s 6.4 GB/s
PC2-6400 DDR2-SDRAM (single channel) 51.2 Gbit/s 6.4 GB/s
Itanium zx1 bus 51.2 Gbit/s 6.4 GB/s
Prototype DDR3-SDRAM (?) 68.224 Gbit/s (?) 8.528 GB/s
PC2-8500 DDR2-SDRAM[12] 68.264 Gbit/s 8.533 GB/s
PC2-4200 DDR2-SDRAM (dual channel) 68.272 Gbit/s 8.534 GB/s
PC4000 DDR-SDRAM (dual channel) 68.6 Gbit/s 8.575 GB/s
PC2-5400 DDR2-SDRAM (dual channel) 85.328 Gbit/s 10.666 GB/s
PC2-6400 DDR2-SDRAM (dual channel) 102.4 Gbit/s 12.8 GB/s
PC2-8500 DDR2-SDRAM[12] (dual channel) 164.528 Gbit/s 17.066 GB/s

[edit] Notes

  1. ^ In telecommunications, 1 kbit/s = 1 000 bit/s, NOT 1 024 bit/s. Thus, all values below use metric prefixes. See this section. Similarly, kB, MB, GB mean kilobytes, megabytes, gigabytes, not kibibytes, mebibytes, gibibytes.
  2. ^ TTY uses Baudot code, not ASCII. This uses 5 bits per character instead of 8, and one start and 1.5 stop bits.
  3. ^ a b c d 56K modems: V.90 and V.92 capacity can only be achieved when the upstream (service provider) end of the connection is digital. In addition, certain telecommunications administrations limit the signal strength the modem can transmit onto the telecommunications circuit, which in turn limits the actual maximum data rate to less than the theoretical maximum. In the USA, this limited the possible downstream maximum to 53.3 kbit/s.
  4. ^ Serial, 1 start bit, 8 data bits, 1 stop bit: therefore 10 bits needed to transmit each byte. The exception is 110 baud which uses 2 stop bits or 11 bits per byte.
  5. ^ ISDN: A basic rate interface (BRI) provides 2 'B' channels and one 'D' channel. Each B channel provides 64 kbit/s bandwidth and the 'D' channel carries signalling (call setup) information. Primary rate interfaces (PRI) vary depending on whether the region uses E1 or T1 bearers. In E1 regions, the PRI carries 30 B-channels and 1 D-channel; in T1 regions the PRI carries 23 B-channels and 1 D-channel. The D-channel has different bandwidth on the two interfaces.
  6. ^ a b c d e Note that PCI Express lanes use an 8B/10B encoding scheme.
  7. ^ SATA and SAS use an 8B/10B encoding scheme.
  8. ^ Fibre Channel 1GFC, 2GFC, 4GFC use an 8B/10B encoding scheme.
  9. ^ Fibre Channel 10GFC uses a 64B/66B encoding scheme, is not compatible with 1GFC, 2GFC and 4GFC, and is used only to interconnect switches.
  10. ^ FireWire (IEEE 1394b) uses an 8B/10B coding scheme.
  11. ^ SATA uses an 8B/10B coding scheme.
  12. ^ a b Not part of official standard, modules intended for overclocking enthusiasts (single channel)
  • The BYTES column contains an idealised throughput because it ignores protocol overhead and simply counts transferred bits in 8 bytes groups. This amount contains not only "useful data" for the transfer endpoint but includes any "system data" the transfer uses to encode, control, verify or correct the transferred "useful data", thus the preceived transfer rate is always lower than the value indicated.
  • Actual frame relay connections will vary in throughput from 8 kbit/s to 45 Mbit/s depending on configuration. Most commonly below 2 Mbit/s.
  • ADSL connections will vary in throughput from 64 kbit/s to several Mbit/s depending on configuration. Most commonly below 2 Mbit/s. Some ADSL & SDSL connections have a higher bandwidth than T1 but their bandwidth is not guaranteed, and will drop when the system gets overloaded where as the T1 type connections are usually guaranteed & have no contention ratios.
  • DOCSIS 1.0 specifications include technology that was available in the 1995–1996 timeframe, and have become very widely deployed around the world.
  • DOCSIS 1.1 specifications provide improved operational flexibility, security, and Quality-of-Service (QoS) features that enable real-time services.
  • DOCSIS 2.0 specifications provide dramatically increased upstream throughput for symmetric services.
  • DOCSIS 3.0 specifications are currently in development at CableLabs and will include a number of enhancements, most notably, channel bonding and support for IPv6. Channel bonding provides cable operators with a flexible way to increase upstream and downstream throughput to customers, with data rates in the hundreds of megabits and potentially gigabits per second.
  • Satellite internet may have a high bandwidth but also has a high latency due to the distance between the modem, satellite & 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 & ISDN.
  • Some speeds in the list appear to be incorrect in comparision, Eg: The marketed speed for Gigabit Ethernet is known to be it's full-duplex combined speed. Compared to most other listed datarates where the simplex rate is used. Eg: Fast Ethernet is 100 Mbit/s but can achieve 200 Mbit/s combined speed.

[edit] Decimal vs. Binary Prefixes

Bit rates
Decimal prefixes (SI)
Name Symbol Multiple
kilobit per second kbit/s 103
megabit per second Mbit/s 106
gigabit per second Gbit/s 109
terabit per second Tbit/s 1012
Binary prefixes
(IEC 60027-2)
kibibit per second Kibit/s 210
mebibit per second Mibit/s 220
gibibit per second Gibit/s 230
tebibit per second Tibit/s 240

“Metric” (aka decimal, SI, power of 10) prefixes are commonly misused when referring to binary quantities, i.e. computer data file sizes.

“kilo” actually means one thousand, “mega” means one million, “giga” is one billion, and so on.

However, when referring to computer data quantities, people will often say “one kilobyte” or write “1 KB”, but actually mean 1024 bytes, for example.

This misuse started decades ago, essentially due to the fact that computer data quantities are based on the power of 2, yet metric prefixes, based on the power of 10, were used for these quantities. Microsoft is probably the most noteworthy responsible party - their Windows operating systems still misuse the metric prefixes.

In 1999 the IEC introduced a formal prefix standard (IEC 60027) for binary numbers, which became an IEEE standard in 2005 (IEEE-1541), ergo:

1024 bytes is a kibibyte (KiB), 1024 KiB is a mebibyte (MiB), 1024 MiB is a gibibyte (GiB), 1024 GiB is a tebibyte (TiB), etc.

For example, Kilobyte can refer to either 1000 bytes or 1024 bytes in common speech, however the IEEE has recently defined all the kibi-, mebi-, etc. prefixes to mean 1024 and the kilo-, mega-, etc. prefixes to mean 1000, to stay in line with the rest of the metric system and end the current confusion.

Much confusion and miscommunication should end when these standardized binary number prefixes come into common use.

All of the bandwidth values listed in this article are true metric quantities, i.e. a kilobit = 1000 bits, NOT 1024 bits; also, a kilobyte = 1000 bytes.

[edit] See also

Retrieved from "http://en.wikipedia.org../../../l/i/s/List_of_device_bandwidths.html"
In other languages