Stress test at idle and OCd - Blue Screen??

area512003 · 30 Sep 2011 at 12:28

Asus P5QL Pro
Q9550 EO Revision
4 x 1024MB Corsair XMS 2
Tagan 880W PSU
Geforce 560Ti
5 x 120mm fans
Tuniq 120 HSF

Can someone please help me as I am puzzled as to why my rig above boots into Windows 7 no problem at stock speeds and OC'd (3.4GHz) but blue screens on me when stressed in programs like Prime 95/3D Mark Vantage most of the time even at stock speed :confused:

I have reflashed to different BIOS, messed with all types of voltage/FSB adjustments etc in my BIOS and used a different memory brand and the same blue screen happens when stress testing :mad:

If it helps, I had a Q6600 in there until yesterday and swapped it out for the Q9550. Did not have any major problems before but the FSB was maxed out at 350FSB on the old Q6600 B3 Stepping @ 3.15GHz. With the Q9550 being an 8.5 Mulitplier, that only allows a small OC to 2.975GHz. Is the mobo FSB limited??

To put a spanner in the works, 10% of the time I stress test it and it will work in Prime95 without issue? :confused:

Maybe PSU struggling with Power Draw needed for Stress testing causing blue screen?

C64 · 30 Sep 2011 at 13:46

I am presuming you cleared cmos after you put the new chip in ? higher fsb + 4 sticks of ram needs more north bridge voltage probably or investigate which bios is best for a q9550 maybe only one is any good also might just be a fsb hole try higher clocks etc like 8.5 x 400

area512003 · 30 Sep 2011 at 14:08

Thanks for that C64.

Have not tried over 400 FSB but I do have some Kingston Hyper X 1066 sticks to try if there maybe a FSB Hole under 400.

What sort of voltage would you recommend for the the North bridge?

C64 · 3 Oct 2011 at 01:28

You shouldn't need to touch the nbridge really at most probably up it 2 notches from auto same goes for cpu pll it's normally all about the cpu core voltage

area512003 · 3 Oct 2011 at 11:05

Thanks for your help C64.

I have spent the best part of 2 days trying to resolve this problem but whatever adjustments I do, the chip is only stable at max FSB of 376 with 1066 DDRII or 800 DDRII which is only 3.2GHz. :mad:

Also changed PSU, gone way over 400FSB, changed all types of voltage settings in the BIOS as per other peoples experiences but will always blue screen in Prime 95 above 376FSB.

All I can think is the mobo or cpu is limiting the OC. Next thing to do is buy another 775 mobo.

Strangely, the message in the blue screen is always "IRQ not less or equal" :confused: