Graphics Cards with PCI Express 2.0: x1, x4, x8, x16. How much is necessary?

[RussianSensation]

I. Computerbase - (Click Next after Test Setup for a full review)

II. TechPowerUp - Nvidia PCI Express 2.0 scaling (x4, x8, x16)

III. TechPowerUp - AMD PCI Express 2.0 scaling (x4, x8, x16)

III. Toms Hardware - PCI Express 2.0 scaling x8 vs. x16

IV (a). HardOCP - GTX 480 SLI PCIe 2.0 Bandwidth Performance - x16/x16 vs. x4/x4


IV (b). HardOCP - GTX 480 SLI PCIe 2.0 Bandwidth Performance - x16/x16 vs. x8/x8


IV (c). HardOCP - SLI & CFX PCIe 2.0 Bandwidth Performance - x16/x16 vs. x16/x8


V. Legion Hardware - P67 chipset 16x/8x vs. 16x/4x. Discussion thread here.

Conclusion: Soon Ivy Bridge will arrive with PCIe Gen. 3.0. However, based on modern cards and performed testing thus far, the time has not come to declare PCIe 2.0 8x/8x (or even 16x/4x) obsolete just yet. Most of these reviewers found that we have a lot of usable PCIe 2.0 bandwidth for single cards even at PCIe 2.0 x4, and certainly at PCIe 2.0 x8 with multi-GPU video card configurations. You may find a 5-7% difference between PCIe 2.0 x4 and x16 and probably around 2-3% between x8 and x16.

*** Most of you already know these findings. I figure we can consolidate a lot of PCI Express 2.0 scaling reviews into this one thread. Feel free to add any more reviews as they spring up. I'll update this thread when PCIe 3.0 reviews with next generation of cards pop up. ***

 

[96Firebird]

I have a new gen. 3 ASRock motherboard coming for my new build, which has 2x PCI-E 3.0 slots in it. I figured it wasn't necessary, but its still nice to know I have it. Just in case, for some unforeseen reason, 2.0 gets saturated with 28nm cards...

 

[pantsaregood]

The amount of bandwidth provided now is ridiculous. PCI-E 8x to PCI-E 16x yielded a 0.3% improvement on some of those benches. PCI-E 2.0 x4 is actually the same speed as AGP 8x was, meaning that despite AGP being abandoned almost ten years ago, we are just now reaching the limit of its bandwidth. We aren't even close to pushing PCI-E 1.0 x16 bandwidth.

 

[Meaker10]

What about minimum frame rates?

 

[RussianSensation]

What about minimum frame rates?

The 3 Reviews done by HardOCP and Computerbase each have time vs. FPS graphs. Click on those and you should have a better idea of the performance across a period of time.

 

[Arkadrel]

Graphics Cards with PCI Express 2.0: x1, x4, x8, x16. How much is necessary?

Good question.

I think it depends on the cards. If you use a 590 or 6990, you ll probably see a much bigger effect from 8x -> 16x, than you would with a 5770 or so.

Does card Y need X amount of bandwidth? answear depends on Y card.

Maybe with newer gen of more powerfull cards, it ll matter even on single gpu based cards.

Conclusion: Soon Ivy Bridge will arrive with PCIe Gen. 3.0. However, based on modern cards and performed testing thus far, the time has not come to declare PCIe 2.0 8x/8x (or even 16x/4x) obsolete just yet. Most of these reviewers found that we have a lot of usable PCIe 2.0 bandwidth for single cards even at PCIe 2.0 x4, and certainly at PCIe 2.0 x8 with multi-GPU video card configurations. You may find a 5-7% difference between PCIe 2.0 x4 and x16 and probably around 2-3% between x8 and x16.

I agree with this though, 16/16 is enough for now.

If PCIe 3.0 is much more costly to add, you have to question if its actually something you want on the motherboard.

Kinda like how haveing 14 USB 2.0 ports is silly, why bother adding all that cost, when 99.99% of all people never need to hook up 14 usb devices at once? Same thing with thunderbolt, useless expensive tech, that ll just make motherboards cost more.

 

[lamedude]

I need a PCIe3 32x card so can I load all of Rage's textures into RAM at once. And they said we would never use AGP texturing again.