Random restarts on overclocked Q6600 and Asus P5N-D

[Vamp]

I've tried overclocking my Q6600 to 3.0ghz with:

FSB Mem: Unlinked
FSB Mem Ratio: Auto
FSB QDR: 1333
Multi: X9
Mem: 800
Vcore: 1.325v
Dram: 1.9
ht: 1.3
nb: 1.3
sb: 1.5

The system runs perfectly for awhile until I get a random restart with no BSOD. These can occur between half an hour and a couple of days. My temperatures are ok, with Everest reporting the CPU to be at 22 degrees when idle.

Any ideas? If not, could anyone suggest what settings to use to achieve a lower clock, like 2.8ghz?

I've heard the CPU and board should work well when OCing, and I originally got the system overclocked from my dealer who ran it through a 24 hour stress test with no problems.

I've been using stock lately and have tried overclocking again myself to see if I can get any luck.

[Cabalo]

most probably the ram timings .
have you tweaked those ?

[clocker]

When overclocked, almost anything could be the root cause.
You could try relaxing the RAM timing and link, if only to take it out of contention.

Could be the PSU, too.

[zmonkey]

I'm going to suggest a bit higher Vcore, too, 1.4V should be plenty, but would also agree w/ other comments, especially PSU if your case is loaded with a lot of high wattage hardware.

[Vamp]

I have 2X 2GB Transcend sticks of RAM.

CPU-Z shows timings at 400mhz to be 5-5-5-18-23

[lynx]

The secret (though obviously not that secret or I wouldn't be telling you) when overclocking is to find the stable limit of each part. In order to do this you need to be absolutely sure that other parts of the system are nowhere near their limits.

That usually involves dropping the memory speed and the FSB speed while checking the limit of the CPU, but you are out of luck with the FSB because of the lack of options on the multiplier. You should slow down the memory to rule that out as the possible cause, and anything else not directly controlled by the FSB speed. I'm not sufficiently familiar with the options available to tell you what else you can slow down.

[saulin]

I have 2X 2GB Transcend sticks of RAM.

CPU-Z shows timings at 400mhz to be 5-5-5-18-23

So you have 400Mhz RAM. or is it overclocked to 400Mhz? I overclocked everything but my RAM. I'm actually running it underclocked because my RAM sucks and it won't run 150Mhz overclocked and is either that option or to run it underclcoked because my front side bus is at 480Mhz.

Check to see what voltage your ram needs, make sure you have the recommended voltage and timings. If it still reboots, then it could be something else. Can your mob up the north bridge voltage? If so try upping it a little.

I Have a Asus P5Q Deluxe and it has so many options and voltage settings. I got my Q9550 to 4080Mhz and I'm not sure how much more it could go. I just left it there. NB voltage is very important for stability. memory timings as well. Also memory voltage. Sometimes you need to disable certain bios options as well as I found with my RAM.

Have you actually done any stress tests? How hot does your CPU get under load?