# PCI-2.0 Card in PCI-3.0 Slot/ How will it work?



## BradleyW

Quote:


> Originally Posted by *hotrod717*
> 
> Just wondering how my PCI-E 2.0 gpu would work in a new motherboard that has x16 PCI-E 3.0 slots? Will it work? I realize it wouldn't perform as well as a 3.0 gpu, but what differences in performance could i expect compared to a 2.0 card in a 2.0 slot?


Yes it works.
If you out a 680 in a 2.1 x16 and a 3.0 x16, you would see no difference.

You might see a 1fps drop at an extreme res of 5000xwhatever. But the chance is slim. In fact, did you know a 2.0 slot at 4x reduced a GTX 580 by only 1 frame on average at games max out at 1080p?


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## trumpet-205

Quote:


> Originally Posted by *hotrod717*
> 
> Just wondering how my PCI-E 2.0 gpu would work in a new motherboard that has x16 PCI-E 3.0 slots? Will it work? I realize it wouldn't perform as well as a 3.0 gpu, but what differences in performance could i expect compared to a 2.0 card in a 2.0 slot?


It will work. It will just slow down to PCIe 2.0. Performance is the same unless you are running 2 or more GPUs.


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## Blameless

You mean PCI-E. PCI also has multiple revisions, but it's a totaly different slot/bus.

Anyway, PCI-E is fully backwards compatible, a PCI-E 2.0 card will run fine, at full PCI-E 2.0 speed, in a PCI-E 3.0 slot.


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## Disturbed117

It should work fine, Even in a x8 slot. Since PCI-E 3.0 x8 has the same bandwidth as PCI-E 2.0 x16.


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## hotrod717

Thanks for all the replies. I am not knowledgable about graphics. What is the advantage of having x16 slots if they don't perform better than x8. Or at least not significantly better. I would think that x16 would perform 2x better than x8. Can some one point me to a thread that would explain how all of this works?


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## hotrod717

Quote:


> Originally Posted by *hotrod717*
> 
> Just wondering how my PCI-E 2.0 gpu would work in a new motherboard that has x16 PCI-E 3.0 slots? Will it work? I realize it wouldn't perform as well as a 3.0 gpu, but what differences in performance could i expect compared to a 2.0 card in a 2.0 slot?


Quote:


> Originally Posted by *Blameless*
> 
> You mean PCI-E. PCI also has multiple revisions, but it's a totaly different slot/bus.
> Anyway, PCI-E is fully backwards compatible, a PCI-E 2.0 card will run fine, at full PCI-E 2.0 speed, in a PCI-E 3.0 slot.


I did say PCI-E. ?


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## Disturbed117

Quote:


> Originally Posted by *hotrod717*
> 
> Thanks for all the replies. I am not knowledgable about graphics. What is the advantage of having x16 slots if they don't perform better than x8. Or at least not significantly better. I would think that x16 would perform 2x better than x8. Can some one point me to a thread that would explain how all of this works?


Each new PCI-E version Doubles the Bandwidth of previous Generations. It's not that x16 slots don't perform any better, It's just graphics cards don't fully saturate current PCI-E 2.0 x16 slots.


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## Hatfieco

Distrubed nailed it. Current cards hardly saturate a pci-e 2.1 8x slot. In almost every benchmark/review ive seen there is less than a 1% difference between 8x and 16x in the 2.1 pci-e. By the time 3.0 is needed it wont be bandwidth holding us back but instead processing power. In short your golden, go for it.


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## Stinger5150

This post is just what i was looking for great info..............


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## anubis1127

Necro this thread, just like that 3dfx logo. I like it.


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## vr335

(fully realizing that this is very old thread, but still - I found this post looking for this exact question on google, so chances are others still find it as well)

The answer is: not necessarily, depends on the motherboard. It should work in theory, but I have my own motherboard MSI H87-G43, with 2 PCIe slots, one 3.0 another 2.0. My video card NVidia GTX 480 works ok when it's put in slot 2.0, but there's no video signal on it when it's in 3.0.


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