Thinking of adding a PCI card to your old(ish) PC?
 

Altruistic gesture for the day:

I thought it would be a good idea to share a potential "gotcha" for anyone intending to add a PCI card to upgrade an older PC - WiFi or standard network card, USB or Firewire card for example.

Be advised that there are 4 (soon to be 5) versions of the conventional PCI local bus specification, in addition to the newer PCI Express and the niche PCI low-profile (not forgetting the mini-PCI spec. for laptops).

The current version of the conventional PCI specification is 2.3 since early 2004. There will be PCI 3.0 before PCI Express achieves world domination, but that is not released yet (I think).

Older PCs will have PCI slots with:
Version 2.0 (up to about 96/97, e.g. Pentium Pro, Pentium II)
Version 2.1 (up to about 2000 e.g. PIII, Celeron)
Version 2.2 (2000 - 2004 e.g. P4, Athlon)

The problem is that a version 2.1 card will not work in a 2.0 slot and a version 2.2 card will not work in a 2.1 or 2.0 slot!

Forward and backward compatibility is a little more complex than that, but I won't bore you with 5v and 3.3v & 32 / 64 bit buses.

So before buying a PCI card to put in your older PC check 2 things:

1) what version of PCI slots does my PC have?
2) what version of PCI is the card I want to buy?

Unfortunately, this is often easier said than done. I know, that's why I have hardly any hair left, and it's grey!

SD