PCI Interface

[helms]

Hi,

Is PCI 2.2 backwards compatible with PCI 2.1?
Because some network interface cards only state PCI 2.2 however this network interface card supports both

So does that mean the ones that state PCI 2.2 only can also be used in PCI 2.1?

 

[evongugg]

I found out that most PCI based cards are PCI 2.2 compliant,
which means that they won't work at all in older (including many Slot 1
pentium II/III boards) PCI 2.1 systems (motherboards now are both
2.1,2.2, and many are 2.3 compliant as well). Usual symptom is that the
desktop system will refuse to even post once you install the card, which is exactly what I was seeing. From what I could find, one
major difference between the two specs has to do with voltage (3.3v vs.
5v).

 

[Ruune]

if both v2.1 and v2.2 are listed on the card specs, then you can use the card in either. If the card says 2.2 and doesnt mention 2.1, then it is probably a 3.3v card- so it'll only work in a PCI 2.2 slot. PCI 2.2 will do 5v or 3.3v, whereas 2.1 will only do 5v... per spec requirements

I know many will read this and say "AH! But PCI 2.1 WILL run 3.3v!!!" This is true to a point- the enabling of the 3.3v rail was encouraged in the PCI 2.1 spec. It wasnt until 2.2 that it was required. So, many MB manufacturers opted not to.

Back to the initial question- the card specs you're showing are probably designed around a 2.1 spec, but since the 2.2 SLOTS will run 2.1 or 2.2 cards, both are listed. So you should be ok- Just remember, slots are backwards compatible with older cards... but vice versa.

 

[helms]

So what you are saying is that 2.1 cards will work on 2.2 motherboards but if its the otherway around then its unsure. So a 2.2 ONLY card may or may not work on a 2.1 motherboard depending on whether the 3.3V rail was enabled by the manufacturer.

Thanks for the help

 

[Ruune]

exactly!