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Underclocked CPU BSOD with Prime95

Hey guys, could use a little help. My wife was vacuuming a couple days ago, and it tripped our breaker. Afterwards, every time I started my PC, it would freeze at the windows loading screen. both the CPU and the memory were both OC'ed at the time. I then set everything to the default speeds in the bios, after that, windows would load, but as soon as I put any stress on the CPU (Prime95 test) it BSOD's. I tried even lowering the clock specs even more, with the same problem.

Here is my rig:

Intel i7-860 CPU
corsair H50 cooler
gigabyte GA-P55A-UD3 mobo
4 sticks of 2gb kingston hyperx 1600 DDR3 ram
evga gtx 580
kingston 64gb SSD
4 other HD's, 3 SATA, 1 IDE
Corsair 850w Power Supply
Windows 7 ultimate 64 bit
internal card reader
samsung blu-ray burner
samsung DVD burner

Where is what i've tried so far:
changed powerstrip, power cord, and electrical outlet
reset cmos
installed windows on a different hard drive
tried using a different PS (antec earthwatts 750) and video card (GTX 275)
tried with 1 stick of ram (then changed out that stick)
tried disconnecting all the HD's except 1, and all the dvd burners.
tried disabling all but 1 processor core in the bios

I'll start running memtest after I get done with this post.

Most of the time the BSOD says "machine check exception", although a couple times it did just say "hardware error" and once "A clock interrupt was not received on a secondary processor within the allocated time interval." I suspect the problem is the mobo. My guess is the processor isn't getting the juice to run at higher speeds.Its probably going to take a good month to get a new mobo from gigabyte, so hopefully that's the problem, not the processor, or something else. I always thought that processors pretty much either work, or they don't, and if my PC is making it to windows, then it should be fine. Is this a correct assumption?

Any help/thoughts/suggestions?

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  1. You've done a good job of investigating the problem so far. I think you've narrowed it down to your motherboard or CPU. (Assuming your memtest clears your RAM... keep in mind that you should run that test long enough that so that it clears several times.)

    The only way I can think of to rule out motherboard or cpu would be to either put your CPU in another system and stress it or to put another CPU in your motherboard and test it.

    Keep in mind that both the CPU and motherboard could be damaged. :(

    You are going to figure this out. :) I'm glad you didn't lose your data.
  2. Best answer
    Just to update this thread

    I called gigabyte about an RMA for my mobo, they said it would take several days to get the RMA number, and then 2-3 weeks AFTER they received the board to determine the problem, and fix it if necessary, and then a week or so to send it back. I found this turn around totally unacceptable, so I called intel to see if they could assist with troubleshooting. For 25 bucks, they cross-shipped me a new i7-860, I got it the next day. after installing, the problem turned out to be the mobo. After checking the recent reviews on my gigabyte mobo on newegg (last 8 or so are all 1 egg, they seem to all be breaking down) I decided to get an EVGA P55 SLI from newegg instead of dealing with more potential problems. everything is up and running, and faster than ever.

    I find Intel's customer service simply amazing. They sent me a new i7 knowing full well I had not isolated the problem, and even knowing I had "inadvertently" OC'ed it. (according to the intel guy, who really knew his stuff, by increasing the memory multiplier to get my memory to 1600, I was "OCing" the CPU, because the memory controller is on the chip, and only designed for 1333. Makes sense, but not something I thought of, I just knew to keep the memory less than 1.64 volts, although the number he gave me was 1.5 volts for lynnfield).

    TLTR: it was the mobo, and intel Customer service rocks.

    Edit: O yea, and I got a new APC UPS :)
  3. Best answer selected by Leaps-from-Shadows.
  4. This topic has been closed by Leaps-from-Shadows
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