Mtbiker650

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So, I have my 990x at 4256MHz, and my voltage at 1.243. Idle temp is 35C and after running prime 95 for about 5 min my pc just reboots itself. The temp never goes above 70C. I'm just wondering if anyone know what would make it do that. I don't get a bsod, it just reboots.
 

Mtbiker650

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Mine makes it through boot and runs just fine. It's only when I run p95 for about 5 min... That's when it reboots. I tried upping and lowering the voltage and got the same problem. Honestly don't know what it could be...
 

lowjack989

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When you run prime95 it takes the stress level up to immense proportions....It is the tell tale of an unstable OC...Your machine could be unstable and still function until it is pressed to its limits using a program like prime95...BTW...Unstable OC's tend to corrupt data...Try lowering the clock on the CPU? What are your OC settings in BIOS the unstability can be a RAM issue as well....
 

lowjack989

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Your reboot is due in part to ASUS's CPR BIOS utility..its kinda like a failsafe for bad OC's...BTW for what its worth just because I have used AMD as an example, it doesn't mean I don't know what I am talking about..Weather it be the CPU, RAM, MOBO, etc....It is for sure an UNSTABLE OVERCLOCK
 

Mtbiker650

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I put it to default and ran p95 for 8 hours. No problems. Do you think it could be some of the OCP or speed step settings in the bios or something like that? Or possibly something with my memory?
 

tlg

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Try testing Prime95 at that 4256mhz clock speed but put the voltage to 1.26, lets say. If it stops rebooting it means u didnt have enough voltage, if it keeps rebooting then it could either be a RAM problem (try to force the ram multiplier under at x8 or x10) or simply a problem issued by your motherboard's wrong voltages (which would mean that ur mobo doesnt manage to OC properly because its defective.) You know... when you OC ur CPU some things in ur motherboard are also getting clocked higher.

And it is indeed weird that its simply a reboot happening and nothing more. Did you check you motherboard's temperature when your CPU is OC'ed and running prime95? You can do that with "CPUID HWMonitor" program my mobo is at max 50C when my cpu is at stock, but when i OC it, my mobo goes up to 65-66. If it goes much higher than this is could be an issue that makes ur mobo order a shutdown to stop the heating, because high temps there will not cause BSOD in windows.
 

tlg

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Sorry for double post.

I just saw that your specs is a 1600mhz G skill ram. I believe that in order to clock an i7 990x to 4.2ghz you would need a ram that can run faster than 1600mhz, as the BLCK would be quite higher than 200 i belive... x8 RAM multiplier and 200mhz BLCK will clock ur RAM to 1600mhz, so if ur over 200mhz BLCK force ur ram to operate under a x6 multiplier (if something so slow exists) and once ur CPU oc is stable... go buy a ram that run smooth at 2000mhz or even 2200 (like a dominator gt 2000mhz 8cas).
 

Mtbiker650

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Well, with it overclocked the temps didn't go above 70, I haven't messed with it much for a while cause I'm installing a WC setup, I checked the settings to see if something would make it shut down at that temp but couldn't find anything. As for the memory, I haven't messed with it much. Just upped the clock to 1600 which is what it's advertised at. I really don't know how to do much more with the memory...