PCI Slots & ATA 100

[Guest]

It is my understanding that a PCI slot runs at about 1/3 of the FSB speed (or some fractional percentage less than full FSB speed). If I plug an ATA 100 PCI card in a PCI slot on my ABIT BF6 motherboard running a FSB speed of 100 MHz, can the ATA 100 board with a hard drive that can burst to 60 or 80 MB/s actually work at full capacity in a PCI slot? I know we are talking MHz and MB/s, but could someone please help me understand how this works?

Please forgive me if this is a stupid question.

dwhunt

 

[delpart]

ATA100 and PCI are different bus interfaces on the motherboard. PCI is for slot cards and ATA is for hard drives. PCI has many different speeds but the number 133Mb/s comes up in my mind as the current throughput. Older and slower speeds are out there. ATA (AT Attachment Interface) is the spec for hard drive throughput also measured in Mb/s and maxes out at about 66.7 Mb/s.

en Xristos

 

[Crashman]

PCI bus runs at 33MHz and 133MB/s. Your board supports several bus dividers, such as 1/3 for a 100MHz FSB or 1/4 for a 133MHz FSB, to make it stay at 33MHz. An ATA100 board will never use all 133MB/s, but it does share with other devices on the PCI bus.

What's the frequency, Kenneth?

 

[Guest]

The FSB speed is currently set at 100 MHz. I am mainly trying to understand how the PCI throughput can be 133 MB/s when the PCI bus is running at 33 MHz.

dwh

 

[Crashman]

Megahertz is Mega Cycles per Second. The PCI bus is 32 bits wide at 33MHz. 32 bits/8 = 4 bytes. 4 bytes x 33MHz = 133MB/s

What's the frequency, Kenneth?

 

[Guest]

Exactly what I was looking for.

Thanks Crashman!

dwh