AsRock x79 Extreme9 PCIe 3.0 question

[Onyxtwo]

I recently purchased an AsRock x79 Extreme9 with a 3930k. After running a few benchmarks I noticed my graphics cards were running @ PCIe 2.0. I've checked that the bios is set to Gen3 on the PCIe lanes, reinstalled graphics drivers, etc. I've read a few posts about the registry hack to enable 3.0 on x79 boards, but when I use it, it crashes the hell out of my computer. The system would become unresponsive 2 seconds after loading into windows and restart itself endlessly. Here's my question - I was looking into buying another graphics card to run 3 way SLI (GTX 680). With the PCIe lanes only running in 2.0, wouldn't that bottleneck the cards? The 3rd PCIe lane is wired for 8x @ 2.0 (should be 3.0). Is there another fix for this, or is it an Intel/NVidia issue?

Current Setup -
AsRock x79 Extreme9
Intel 3930k
Corsair H100i
Corsair Dominator Platinum 16GB
EVGA Geforce GTX 680 4GB SLI
OCZ ZX 1000w PSU

[- wardog -]

Have you seen the below:

Geforce 600 Series Gen3 Support On X79 Platform

[profJim]

^^+1^^
Excellent find!!

[parsec]

The so called "support" for PCIe 3.0 on boards like this, without an extra chip to provide PCIe 3.0 support, is like saying the board supports eight core CPUs. Sure, if you have an eight core CPU.

From the X79 Extreme 9's Overview page:

PCI-E 3.0 requires both a supporting CPU and motherboard at the same time.
Currently Intel® Socket 2011 Sandy Bridge-E Processor doesn’t support PCI-E 3.0, but this motherboard is already PCI-E 3.0 hardware ready.
It depends on Intel® CPU to enable PCI-E 3.0. Please check Intel® website for information on future CPU updates and releases.

Can someone explain to me how a registry hack can possibly provide PCIe 3.0 support?

Gawd help Intel if Ivy Bridge-E CPUs are not socket 2011...

[profJim]

Here's my question - I was looking into buying another graphics card to run 3 way SLI (GTX 680). With the PCIe lanes only running in 2.0, wouldn't that bottleneck the cards? The 3rd PCIe lane is wired for 8x @ 2.0 (should be 3.0). Is there another fix for this, or is it an Intel/NVidia issue?

Check out HARDOCP - PCI Express 2.0 vs 3.0 GPU Gaming Performance Review where they used:

• single-GPU Geforce GTX 680 and Radeon HD 7970 video cards
• dual-GPU GeForce GTX 680 SLI and Radeon HD 7970 CrossFireX
• triple-GPU setups of GeForce GTX 680 3-Way SLI and Radeon HD 7970 3-Way CrossFireX

Small consolation from their July 2012 conclusion:

PCIe 3.0 is a great evolution, one day it may actually support a better gameplay experience compared to PCIe 2.0, but that day is not today.

They didn't test with Sandy Bridge-E, but their results still apply.