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.
Tom's Hardware's Three-Part, 3-Way Graphics Scaling Series
Part 1, The Cards: Triple-GPU Scaling: AMD CrossFire Vs. Nvidia SLI
Part 2, The Slots: GeForce And Radeon On Intel's P67: PCIe Scaling Explored
Part 3, The Chipsets: P67, X58, And NF200: The Best Platform For CrossFire And SLI
We’re constantly impressed by the performance of Intel’s latest processors, which offer both higher IPC (instructions per cycle) and better overclocking headroom than anything seen previously. This is particularly true in games, where the extra execution resources in Intel's Core i7-990X go unused anyway.
Yet, in spite of the Sandy Bridge architecture's superior gaming performance (or at least better value, since you don't need to spend $1000 on a six-core processor to get equivalent frame rates), many enthusiasts insist on the added expandability of the old LGA 1366 platform. This makes sense in light of the P67’s incredible handicap: namely its 16-lane processor-based PCIe graphics interface.

But do we really need more than 16 lanes? Aren’t eight lanes enough for a single card? If that’s true, expensive and power-robbing PCIe bridges certainly wouldn't be necessary to support multiple cards. We’ve even heard stories that the PCIe 2.0 x4 slot supported through the P67 chipset is adequate for some graphics cards.

Before we move on to see how the P67-based platform stands up against the X58- and NF200-enhanced versions of both, let's get to the basics of PCIe scaling using modern cards on the best-possible gaming processor. This is Part 2 of our multi-card scaling series, but will there be enough graphics performance difference between various slots to justify a Part 3?
- Are Sixteen Lanes Enough?
- Test Hardware And Benchmarks
- Benchmark Results: 3DMark 11
- Benchmark Results: Aliens Vs. Predator
- Benchmark Results: Crysis
- Benchmark Results: F1 2010
- Benchmark Results: Just Cause 2
- Benchmark Results: S.T.A.L.K.E.R.: Call Of Pripyat
- PCIe Scaling Summary
- Bonus Page: Does CrossFire Work At x16/x4?
- Conclusion
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.
3 way would be preferable because if performance is still adequately faster I'll consider it.
http://www.tomshardware.com/reviews/pci-express-scaling-p67-chipset-gaming-performance,2887-10.html
The numbers were there all along!
"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."
http://www.tomshardware.com/forum/2887-56-geforce-radeon-intel-pcie-scaling-explored
I'm going there to delete your quote from my response.
I means, its logical, but mayb not true
Just my 2 cents
Of course, Tom's Hardware has all the cool kit that helps editors overcome those bottlenecks.
that's an interesting question, like a 6950 and a 6970, would it be faster with a 6970 in the first pcie slot or the second.
It might be worth conducting at least two way Crossfire/SLi tests more often in future with new card reviews or, at least, follow-up reviews, though I can imagine it'll delay such articles a little. Perhaps using AMD cards on P67 is limiting their scaling, even if it's already very good (with the 6000 series)? Would using two mid-range cards have the same effect?
This is a mighty popular game. Does EA make reviewers pay them to mention their game in reviews?
For example, would this be the case on LGA 1366, where all the PCIe lanes are on the chipset, and not some going through the chipset and some being part of the CPU package? In real world situations, it's not so important because you'd have less cause to use an x4 in LGA 1366, but for academic purposes, and a better understanding of what's really going on, it could be interesting.