PCI max throughput

Hypothetical here, but I want to understand.

Say I have a hand me down machine, 4 PCI slots, 64-bit 33 MHz PCI.

How much data can that PCI bus handle? System bus is 133 MHz.

I want to use one slot for a SATA II card, and the rest for Gig-E cards, building out as fast a NAS as I can. I think one slot may be AGP2x, so that leaves me 2 for Gig-E and one for SATAT II.

Will I saturate, what is the max bandwidth of the PCI bus?

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you'll certainly saturate the PCI bus before you get anywhere close to full SATA-II speed. (dunno about the gig-E, but suspect it's similar.) i've a similar system and just put in an SATA-II card; my SATA-II drives read at approx. 60-70 MB/sec. much better than IDE drives, so it's worthwhile for my purposes. (not posted as an answer since i don't have time to calculate max theoretical speeds and such.) – quack quixote Nov 8 '09 at 9:49

According to Wikipedia's PCI article and List of device bandwidths, PCI bus bandwidths can be calculated with the following formula:

``````frequency * bitwidth = bandwidth
33.33 MHz * 32 bits = 1067 Mbit/s = 133.32 MB/s
``````

Conventional PCI buses operate with the following bandwidths:

• PCI 32-bit, 33 MHz: 1067 Mbit/s or 133.33 MB/s
• PCI 32-bit, 66 MHz: 266 MB/s
• PCI 64-bit, 33 MHz: 266 MB/s
• PCI 64-bit, 66 MHz: 533 MB/s