GeForce And Radeon On Intel's P67: PCIe Scaling Explored

Features
By Thomas Soderstrom
published

Intel’s Sandy Bridge-based processors dramatically advance gaming value by increasing performance at lower prices than LGA 1366-based configurations. But is the platform it sits on worthy of that CPU? We test three slot configurations to find out.

Benchmark Results: Crysis

Yes, both cards can play Crysis all the way up to 1920x1080 with Very High details and 4x AA. Expect to lose 10% from either card by dropping it in a x4 slot, while the x8 slot gives up only 2-3%.

Though our average frame rates are charted for easy comparison, we often refer to a minimum frame rate of 20 FPS when discussing playability. That’s not possible from either the GeForce GTX 570 or Radeon HD 6950 at 2560x1600.

Note that the performance drop due to switching from a x16 to an x4 slot falls to 6% for Nvidia. AMD still suffers a loss of nearly 10%, even at this GPU-bottlenecked setting.

Thomas Soderstrom
Thomas Soderstrom
Thomas Soderstrom is a Senior Staff Editor at Tom's Hardware US. He tests and reviews cases, cooling, memory and motherboards.
71 Comments Comment from the forums
  • geofelt
    These tests were done with a single card, on X16/X8/X4 slots. Fine.
    But... Who would use anything other than a X16 slot if they had one?
    The only real use for a X8 slot would be for sli/crossfire where the addition of a second card should result in an Increase of performance, not a decrease.
    Reply
  • carlhenry
    it would be nice if you included the GTX 570 in the x8/x8 and x16/x4 test. the 570 flies over the 6950 on the single card config but i was curious how it would do since i think the AMD's scale better than nvidia's. would the 570 still lead because of its advantage? or would AMD even it out because of its scaling (if any) "advantage"
    Reply
  • classicaxe
    ^They already did an article on that man
    Reply
  • joytech22
    Can you guy's do an article on how performance is affected if you SLI/Xfire using PCI-E 16x slots running @ 4x?

    3 way would be preferable because if performance is still adequately faster I'll consider it.
    Reply
  • dalauder
    Good comments. Can we please see 8x/8x and 16x/4x since that comparison is relevant? I get the impression that somehow SLI/crossfire reduces the performance hit of x4 lanes but I'd like to see numbers.
    Reply
  • Crashman
    joytech22Can you guy's do an article on how performance is affected if you SLI/Xfire using PCI-E 16x slots running @ 4x?I think you missed a page then!
    http://www.tomshardware.com/reviews/pci-express-scaling-p67-chipset-gaming-performance,2887-10.html
    The numbers were there all along!

    carlhenryit would be nice if you included the GTX 570 in the x8/x8 and x16/x4 test.Well, you should probably read the linked page too then. There's no point in artifically creating a configuration (by taping lanes or whatever) that doesn't exist in real life, is there?

    "While Nvidia prevents SLI from functioning on PCH-hosted lanes, x16/x4 configurations are completely possible in CrossFire. But should they be? We tested our motherboard in both x8/x8 and x16/x4 configurations to find out."
    Reply
  • dalauder
    Yeah...my bad.
    Reply
  • Crashman
    dalauderYeah...my bad.I didn't mean to call you out to that extent, here's a link to the forum part of this thread:
    http://www.tomshardware.com/forum/2887-56-geforce-radeon-intel-pcie-scaling-explored
    I'm going there to delete your quote from my response.
    Reply
  • rolli59
    Looking forward to see the third article!
    Reply
  • cats_Paw
    Im guessing that 8x lanes are mostly enought. I do belive that it would depend on how fast an actual gpu is, as well as how much ram it has, and how big is its bandwidth.
    I means, its logical, but mayb not true :D. Would be nice to see this test on a GTX560 Ti, since it has a lot of headroom for OC, then compare oced version vs non oced. Also this might be interesting in GPUs that have diffrent versions with more and less RAM.
    Just my 2 cents :D.
    Reply