Graphics slow after OC of i7-920

[bandyOC]

G'day,

A weird issue has occured with my machine. I decided to overclock the CPU which in the process required a BIOS update. I was doing this with a new installation of windows just for the purpose of protecting the original ones.
The specs:

Gigabyte EX58-u3r rev 1.6
i7-920 @ 3.86Ghz
6GB G-Skill DDR3 10600 RAM
Raid 5 on 3 HDD
Geforce GTX 260
Win7 32bit Ultimate

Second boot install for games
Single HDD win 764 bit Ultimate

The CPU runs stable no issues there however since the OC (or the bios update) graphics a very sluggish in games especially there a stutters all over. I made sure not to tuch any graphics or PCIE settings during the OC.

Windows experience index used to be 6.6 for Graphics now 5.8 3D Mark barely runs.

The whole purpose of OC was to be able to run FSX better however now it run on 0.1 FPS!!! The slowest I ever experinced was 13.00 FPS.

Reinstalled card and driver on both OS and reinstalled chipset drivers as well.

In the 32bit OS it still shows 6.6 for experince index but running games is a no go.

What to do?

Thanks

 

[Bobnova]

Check what the QPI Link Multiplier (name may be different) is set to. If it is set to "slow mode" that is your problem.

 

[bandyOC]

Thanks that was part of the issue it was set to Slow mode now I set it to x36 and frame rates have doubled in the GPU test HOWEVER again once the CPU is fully loaded frame rates drop to near zero. The OC guide said set QPI to it's lowest setting they porbably meant x36 not Slow mode.
I think the system is struggling for power as when I run a gpu stress test all seems happy as soon as i run CPU test GPU performace drops. IT seems to me it's not getting enough power.
In aonther test that shows GPU load when without CPU stress it's at a constant 89% during high CPU load it drops to 29%...
The PSU is 700W.
Any thoughts on that?

 

[bandyOC]

OK tried with a true power 850W PSU still no difference.