Computer Shuts Down Suddenly

Hello Everyone,

I'm a newbie to this forum and would like some help. I recently built a home desktop with the following components:

-ASUS Crosshair Forumula IV board (AMD)
-AMD Phenom 965 Black using stock cooler
-Gigabyte Radeon HD6850
-8GB DDR3 Ram
-Corsair TX750 PSU
-60 GB SSD
-1TB Western Digital Caviar Black HDD
-Blu-ray Player

The computer, which is running Windows 7 Ultimate, has been working flawlessly until the past week, it turns off suddenly. It appears to turn off when I am on the internet, or running programs, but doesn't if the computer is just running idle. I also notice that the after it shuts down, the motherboard LEDs (Reset, Power-on, Core Unlocker, and Turbo Key II) are still on. If I attempt to press the power button on my NZXT Tempest case, nothing happens. I need to either pull the power cord or flip the rear switch in order to power up the system.

I downloaded SpeedFan to monitor temperatures, which appear to be in the 30 degrees C range. I'm also not sure what the normal 3, 5, and 12 voltages should be? It shows the 12V to be around 6.5V. Seems low.

Anyone have an idea of what's happening? The PSU fan runs fine, there are no unusual noises coming from the PSU, however my gut tells me that the PSU is the culprit.

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  1. Okay, I used a multimeter to test all the 3, 5 and 12V pins and they all read within normal operating voltages. So the problem doesn't appear to be from the PSU. What else could cause a sudden shutdown? All fans including the CPU stock fan seem to run fine. Is 38 Degrees C normal for CPU temp? Would the system shutdown on a high CPU temp?
  2. Your CPU temp is fine. I suspect that your PSU is the cause. Can you borrow one from someone to test ? Or do you know anyone willing to have youor PSU in their PC for a while to check it that way ? I've seen similar problems several times, and it's nearly always the PSU that was the culprit.
  3. You may need to look abit in BIOS, but you should see a screen that shows voltages. If it is also 6.5v on the 12v rail, then you most surely have a hardware issue.
  4. So you think that it could still be the PSU even though I am reading normal voltage levels from a multimeter? The scary thought I have is maybe a bad motherboard.

    Thanks again!
  5. According to BIOS, voltages are within normal range. Could another possibility be that I need to update the BIOS? Maybe a software issue that is kicking in causing a shutdown?
  6. I would check your temps under load. Download Prime95. Have SpeedFan up and running. Then launch Prime95. What the temps climb, the fastest climbing temp will be your CPU temp (hey, it's not always labeled by SpeedFan correctly hence this step)

    The CPU temp should ramp up to around 70C under load.
    - If it goes way over this there's a problem with how the heat sink is mounted
    - or, if it SHOOTS up to 70C or more in like 1--2 mins there is most Certainly an issue with heat sink mounting

    If your 70C ish and the system doesn't crash after 30 to 60 mins all is well with CPU & heat sink....

    Now let's test your GPU: (my bet on the black out cause...)
    Download FurMark. Down load GPU-Z. Run GPU-Z to monitor the temps. Then run FurMark. Card should run to maybe 85--90C Worst case. If your screen "blacks out" during testing your video card is bad.....

    Let us know the results.....
  7. Okay, I tried a few things tonight. First off, I flipped my PSU so that the intake fan faces the bottom of the case (NZXT Tempest EVo). I also placed it on my desk instead of on the ground (carpet). Initially, when running for about 15 minutes, all was well, until it then shut off suddenly. The next thing I did was turn on a household floor fan and faced it toward the case. So far, so good, it's been about 2 hours and no shutdown. During this time, I also ran the FurMark and GPU-Z.

    FurMark was running full 1080p and my GPU temps went no higher than 70 deg.C. So far, GPU looks good to go, plus PSU ran flawlessly.

    Overall, it seems like it's a cooling issue with the PSU, and the PSU was going into protection mode or something? I don't believe this is good. I contacted Corsair earlier today anyhow and they gave me an RMA number. I'm thinking I should just send the PSU in for them to check. What can hurt? It's still under warranty. I just don't think it's normal for the PSU to be heating up like that. I shouldn't need to keep a floor fan blowing on my case don't you think? Especially since I have a case with a million fans.
  8. STOP: Don't RMA the PS just yet.....

    Does appear you have a temp issue, BUT did you test the CPU temps? (using Prime95 & SpeedFan)

    Very important to test CPU temps too......

    Sounds like your GPU is rock solid, those temp are nice an cool for a FurMark run....

    On the power supply:
    I can't see from the photos of your case on NewEgg, are their vent holes in the floor/bottom panel of your case where the power supply mounts?

    If yes, then orientate the power supply so it's big fan can suck air in thru the bottom of the case (AND be sure that your carpet does Not block those vents when you set your computer on the floor (I use small blocks of wood to assure I have those vents up and clear of my carpets))

    If no vent in the bottom of the case flip the power supply so the big fan sucks are from inside the case above it's fan.
  9. NOTE: your right, your case has very good cooling, very open, lots of fans.....

    You shouldn't have to do any thing special to keep the Corsair cool. It can run at really high temps and still deliver full power.

    Your GPU is happy & cool cranking on FurMark @ 70C (your going to be in the low, low 60Cs in normal games...)

    I just didn't see any CPU temps, so, again use Prime95 & SpeedFan to test those...... (running FurMark only puts a very, very small load on the computer chip (CPU) itself so its not a good CPU test...)
  10. Just Go To CPU Settings and find there is smar fan is off or on ? if smart fan is off then turn on it.
    Gaurranteed it will stop to shuts off automatically
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