Reboot after 20 minutes prime = NB issue?

[blade52x]

So I was testing a 400x9 overclock on my Q6600 trying to minimize voltage. I set 1.39375V in the bios, loaded up prime and it failed after 1 minute... what?! I had that stable 2 days ago for over four hours. I check my bios, and see that I forget to set the proper FSB and MCH voltages. So normally I set +0.15 and +0.15 to each. This time I decided to set +0.20 on the FSB and +0.175 on the MCH and I set 1.3850V in the bios. Everything boots fine, and I load up prime, and cpuz reports 1.344V under load. Everything ran fine, but after 20 minutes the computer just reboot itself.

1) 20 minutes prime small FTT - obviously the computer chip is not highly unstable to cause the reboot. Temps were 67C, 65C, 65C, 67C on the four cores.

2) 2x1GB Ballistix were running at 1000MHz at +0.3V, which was tested stable many times, and I was running small FTT, so the RAM wasn't being pushed anyway.

3) PWM - well if it ran stable for over 4 hours in an ambient about 8F higher then it is right now, I doubt it would be overheating, plus I have a 70mm ghetto mount on top of it.

So, that leaves me with the NB. Is it a typical overheating NB and reboot? Mine is not mounted down all the way (I know, stupid) though it seems pretty secure because it's still being held down by the entire heat pipe system on the P35-DQ6. But I've got my dad going into his work today to cut the crazy cool plate and just stick the piece under the NB to fasten it down completely since either Gigabyte did not send me the acorn nuts to do, or I lost them unpacking (and no hardware stores seem to sell nuts that small).

But anyway, my general question, for prime to be able to run 20 minutes and then reboot - does this sound something typical of being outside of the CPU & RAM?

 

[JLangevin]

Well....

The description would lead me to believe that something is overheating... the question is are you monitoring the NB temps along with the core temps? Have you touched your DIMM's to see if they were hot after the initial reboot? Typically is something isnt quite right, the system will lock, rather than reboot. Im sure you know this.

I know you said you have a 70mm on top of the NB, but give us the actual temps that your NB are running at. I wouldnt say that your CPU is an issue since you are running at the thermal rated norm for 100% utilization.

I would point to either your NB or your Memory. If you can, rig up some sort of cooling to your RAM and see if it becomes more stable? That would at least rule it out.

 

[blade52x]

I'll give it a shot. I actually have a bunch of 40mm fan coming from Ebay which I'm going to setup around various places. Right now I backed down the overclock to 3195MHz, with 1.2125V set in the bios (cores don't even break 60C under load) and the RAM is running 1065MHz 5-5-5-15 at 0.3V, which is actually higher then the speed I was running at 3.6GHz.

So reboot = something is overheating?
And system freeze = unstable overclock not necessarily a heat issue?

The Gigabyte DQ6 had a "system" temp sensor - I'm not sure what that is - but the highest I think I have ever seen is 41C - it's usually in the mid 30s. I don't believe there is a NB temp sensor on this board, and I don't have any kind of thermal tool I could manually insert into there. I guess I should maybe invest in one.

 

[JLangevin]

That has been my experience anyways....

Of course, as you know everyones experiences are going to be different. Your PC when it overheats will actually freeze, THEN shut off when the thermal temperatures reach a certain point.... this is dangerous since we normally turn off such protection when overclocking.

You mentioned that the Memory is rock solid, but its still good to rule it out... For instance, my pc and a friends are IDENTICAL except for a couple of things... I have watercooling, Patriot Extreme Eased Latency, and an 8600GTS, whereas he has an 8800GTS640, Freezer 7 Pro, and XMS Memory. Both of our memory configs are stock at 800mhz... his memory will crap out long before my Patriot does, leaving him with a max stable oc of 3.1ghz and I have reached as high as 3.5ghz.

I wish I could give you more guidance, but of course, without being hands on, its impossible.