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

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: Aliens Vs. Predator

The Radeon HD 6950 takes the biggest hit from reduced bandwidth in Aliens vs. Predator, its PCIe x4 results trailing the same card in a x8 slot by nearly 7%. The GeForce GTX 570 loses only 3% in this same comparison.

Anyone seeking smooth frame rates at our highest AvP test setting will need at least two of these cards running in either CrossFire or SLI. The x16-to-x4 performance difference drops to 2% for Nvidia and 4% for AMD, but that won’t matter to anyone who actually wants to find a playable 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