PC crashes under Prime95, overclocked or not.


So just built this system:

Intel 9450
Asus rampage x48
2X2 GB OCZ Reaper 1066MH 5 5 5 15 RAM
nVidia 8400 (temp while waiting on the new cards)

I thought I would get this bad boy overclocked and ready while waiting for the new cards to come in, well I used the Asus built in tweaker in the BIOS and get great results. 3.2 is a breeze and system performs nicely, temps very managable on zalman air cooler. But when stress testing the PC crashes after about 8 minutes. So I kept throttling the CPU down and the same at every level untill I reached stock speeds and the problem persists. So it is not an overclocking issue, anyone know why a Prime95 would cause a new PC to crash? MB has latest firmware.

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More about crashes prime95 overclocked
  1. Try running memtest86 to check if your RAM is to blame. What PSU are you using? Check your volts using speedfan while stress testing and see if any of the lines are dropping out of spec. Readings should be within about 5% of rail spec.
  2. Thanks for the reply.

    I will run Memtest today and see whats up. I am using a Thermal Take 600W 12ATX PSU
  3. If memtest does come up with a problem. Take out one stick of ram at a time and rerun it to find out which stick is the problem. I'm at work right now, but I now that some motherboards have problems with 1066 ram. Is OCZ under the list of supported vendors with ASUS?
  4. You will probably have to add voltage to either cpu,ram or northbridge.
  5. easymoney9 said:
    You will probably have to add voltage to either cpu,ram or northbridge.

    I think the problem goes beyond low voltage. He has the same problem while running at stock speeds. That would point to something other than volts, unless his board was severely undervolting the CPU.
  6. Just a small tips for ASUS users.
    It is better not to try to OC your system using software or using BIOS automatic tweeking. It is better to OC your system directly from BIOS yourself. This had happened to me with my current system.
    It seems that the software doesn't change all the necessary settings.
    Example :
    You change the FSB from 266 to 333 with 9x. The software still keep the your memory on 800 and etc. and etc and etc.
    Some of the settings are needed to achieve the stability.
  7. Thanks for the replies guys, but you are getting WAY to tecnical for little ol me. Would not know how to increase the voltage for instance...

    Anyhoo, ran Memstest68+. I THINK RAM is not the problem, I left Memtest running and when I came back five minutes later the PC had restarted, that means its fine right? or did it crash? no error reporting or sucessfull post. Just a restart.

    I will have to get more informed about OCing when this is sorted to do that manually. But right now I just want a stable system at STOCK :(


    Thanks for any help.
  8. Two things I have an ASUS MB with OCZ Reaper memory with no issues. It is DDR2-800 though. So the manafacturer should work. I have my Q9450 over clocked to 3.2Ghz right now. One thing to check for is set your voltages manually for the vCore. When Asus Auto Set it it set it to 1.35 which is very high. I set it back to 1.2068 and I run with no issues.
  9. If memtest restarted, you had a problem. It should keep running forever. As previously suggested, you likely have some bad ram. Test sticks individually to check them out. If necessary, test known good ones in different slots to eliminate the oossibility that you have a bad mobo slot. Prime95 will exercise memory, in addition to the cpu.
  10. I ran Memtest again, this time it ran for an 4 something minutes. Pass completed, no errors found.

    So ram is out.
  11. I meant to say 40 something minutes to test my 4GB of ram. I do not think I have faulty RAM.
  12. Ram is ok. Good.

    Next most likely is a cpu heat problem.

    Install some temperature monitoring program. Speedfan is a good one.

    Watch how your cpu temperatures rise as you start pushing the cpu. If it gets too high(65c) it will throttle, then eventually stop. If the heat sink was not mounted properly, this can happen. The 4 pushpins are notoriously hard to install.
  13. well I ran Prime95 again using both large and small FFTs. It seems stable enough now?????! Using small FFTs my MB does beep once and the cursor freezes for a sec then its normal.

    I dont know if I am pleased about the change or disturbed about the incosistensy.

    Here are two screen shots with CPU and Memory settings, temps etc etc.

    Could anyone please recomend a set of calues for a 3.2 overclock with FSB, multiplyer, vCore etc that might be stable? I have overclocked before but I am no where expirienced enough to attempt with this setup. I almost miss the simplicity of my DQ4 and E6400 :sweat:

    Thanks a tone people!
  14. Geofelt, thanks for the info.

    As you can see from the screenshots, my cpu is nice and cool. That screen shot was taken while Prime95 had been running for a few minutes.
  15. Over time, I would expect your temperatures to go down a bit as the thermal compound cures. Looks good there.

    What psu do you have? If speedfan is displaying the +12v line correctly, you are at 11.4, just at the margin of 5% variance.
    As workload goes up, some psu's do not perform well.

    You have a fine CPU there. Do you really need to overclock? If so, all I can suggest is that you do it in small increments.
  16. To be honest, you need to run Memtest overnight around 8-10 hours. It needs to make a couple of full passes through the ram. 40 minutes is not enough time to rule it out. Also as someone else said, don't use software based over clocking programs. Use the BIOS to make any changes. That way you can ensure that you are setting things properly and you wont run into these types of problems. Check out the guide for over clocking to get an idea of what you need to do.
  17. I assume you have your DDR2 voltage set to manf spec.

    Try raising your FSB voltage and your (G)MCH voltage by 0.1 V

    Background: Last night I tried a test in response to a post in "Motherboards and Memory" about a stability problem when using 4 one gig sticks of DDR2. I Had added 2 more sticks to my system and had too raise FSB and GMCH voltage by 0.1 for stability. Last night I checked my system to see which one was effective. With either on set to NORMAL and the other at + 0.1 V ORTHO PRIME would "Die" after 7 minutes and some odd seconds.

    Bottom line I had to increase Both to get a stable memory envirioment.
    My systme a little differrent as I have 4 x 1 Gigs vs 2 x 2 Gigs Ram and I have a Gigabyte P965 MB.
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