PCIe 2.0 vs. 2.1

[JackSpadesSI]

I tried to look for this answer, but couldn't find it...

My motherboard (see signature) has a PCIe 2.0 x16 slot. Can I use a PCIe 2.1 x16 video card, or not?

 

[Absolution75]

Yes, PCI-E is backwards compatible.

 

[JackSpadesSI]

Wouldn't a 2.1 card in a 2.0 slot be forwards compatible?

Backwards would be using a 2.0 card in a 2.1 slot.

 

[tweakboy]

Of course you can do it. !

Your trippin on that PCIe talk.

You can stick a 6800 GT in your mobo, or a 8800 GT or a 590 ......doesnt make much differnce in performance wise,, maybe 1fps or 2fps more. thx gg

 

[betasub]

Wouldn't a 2.1 card in a 2.0 slot be forwards compatible?

Backwards would be using a 2.0 card in a 2.1 slot.

In your first example, forward-compatible would be the 2.0 slot somehow running 2.1 features. However, it's the 2.1 card that is backward-compatible with the limits of the 2.0 slot.

 

[Seero]

Wouldn't a 2.1 card in a 2.0 slot be forwards compatible?

Backwards would be using a 2.0 card in a 2.1 slot.

Be it forward or backward, it is compatible. People use "backward compatible" to refer PCIe 2.1 video card will work on 2.0 PCIe slot.

PCIe v2.1 is created to make sure video cards will work on both v2.0 and v3.0 PCIe slot, just like v1.1 video card works on both PCIe v1.0 and PCIe v2.0.

In other words, PCIe cards that followed PCIe v2.1 specifications are backward compatible to PCIe v2.0 mobo and forward compatible to PCIe v3.0 mobo in the future.

PCIe v2.1 runs at the speed of PCIe v2.0.

AFAIK PCIe v2.1 specification also support backward compatibility to PCIe v1.0 slots.

 

[JackSpadesSI]

Ok, so we've established that a 2.1 card will work in my 2.0 slot.

Now, will it run at reduced features? e.g. am I wasting money by buying a 2.1 card when I should buy a 2.0 card instead?

 

[Seero]

Ok, so we've established that a 2.1 card will work in my 2.0 slot.

Now, will it run at reduced features? e.g. am I wasting money by buying a 2.1 card when I should buy a 2.0 card instead?

No, it runs at the maximum speed 2.0 allows. The card may run 1-3% faster on pcie3.0, but it is not out yet.

 

[BFG10K]

PCIe is generally backwards and forwards compatible like USB. For very old motherboards you may need a BIOS update for new video cards.