|
Explaining Home Computer Bus
Speeds
Published: 18-Nov-2000 (updated 6/1/2001)
Now that you have learned about
network speeds ( see article)
we can examine the common ways network interfaces and other devices link
into the computer. By examining the maximum throughput of various
interfaces like ISA, PCI, and USB, we can determine what network interfaces are inappropriate
for certain bus's. By comparing the speeds in this article with the network speeds article,
you will get a good idea of how fast devices talk to
your computer.  Bus Speed Chart
| BusName |
Width |
Speed*/Sec |
| SCSI-1 |
|
5 Mbytes |
| ISA |
8bit, 8Mhz |
8 Mbytes |
| SCSI-2 |
|
10 Mbytes |
| PCMCIA |
16 bit, 10 Mhz |
20 Mbytes |
| IDE DMA33 |
|
33 Mbytes |
| Ultra2 SCSI |
|
40 Mbytes |
| IDE DMA66 |
|
66 Mbytes |
| PCCard |
32 bit, 33 Mhz |
132 Mbytes |
| PCI 2.0 |
32 bit, 33 Mhz |
132 Mbytes |
| PCI 2.1 |
64 bit, 33 Mhz |
264 Mbytes |
| PCI 2.2 |
64 bit, 66 Mhz |
528 Mbytes |
| |
|
|
| Serial |
1 Bit |
115 kbit |
| Parallel Port |
8 Bit |
115 kbit |
| USB 1.0 (standard USB) |
1 Bit |
1.5 MBytes
12 Mbits |
| Firewire (IEEE 1394) |
Serial |
12.5-50 MByte
100-400 Mbit |
| USB 2.0 |
Serial |
60 MBytes
480 Mbit |
| Firewire (IEEE 1394b) |
Serial |
25-100 MBytes
200-800 Mbit |
*Speed is a theoretical maximum. Various buss' have different overheads
associated with them
Conclusuions
Ethernet NIC's and the
ISA bus
: Some manufacturers actually sell 100Mbps Ethernet cards for an ISA BUS.
As you can see from the chart above,
the ISA bus will max out at 8MBytes/sec. 8MBytes/sec is the theoretical maximum you could ever
get from a 100Mbps LAN card plugged into the ISA bus!
|
Computer Bus and Interface Speeds
Menu: