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A few months ago my computer started randomly powering off, sometimes I would get a few hours, sometimes a few days. I first replaced the power supply (PC Power and Cooling Silencer Mk II) which stopped the issue for a few weeks, but then it came back.

The other day I got a new motherboard (Asus sabertooth x79), CPU (i7 3930k), and got a new graphics card (GTX650) and it still does it, except now I can't even get a few minutes. I tried replacing the power supply again (Corsair CX750) and no luck. I've tried taking out some of the ram and all the ram. Unplugged all the hard drives and still can't get more than a few minutes at best.

When it does power on, I can get into the bios and make changes, I've even gotten to the windows loading screen if it stays on long enough. I do not have a cpu fan/heatsink at the moment, but I don't think that should prevent the system from staying powered on for more than 30 seconds.

Ive also tried different outlets, cables, and even using the power switch from a different case (the old power supply seems to run in another build without issue).

Any help I can get with this would be greatly appreciated

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What power supply exactly did you purchase? Sounds like a case of your power supply cannot provide enough power to your system. – Ramhound May 17 '13 at 12:34
I bought a Corsair CX750 which is 750W and a PC Power and Cooling Silencer Mk II which is 950W – dreadlocks1221 May 17 '13 at 12:35
Why does your system have two power supplies? I assume you mean you had a Corsair CX750 and replaced it with a Cooling Silencer Mk II? If you don't have a heatsink on the CPU then its overheating and automatically shutting off – Ramhound May 17 '13 at 12:44
I replaced my previous power suplply with the Cooling Silencer Mk II and then bought a Corsair CX750 just to be sure (I'm not using both a the same ttime). The CPU isn't overheating because the computer hasn't been on for more than 2 minutes and it is cool to the touch – dreadlocks1221 May 17 '13 at 12:48
Well the Cooling Silencer Mk II so now you likely running into not being able to provide enough power. Your CPU needs a heatsink and a fan..... until you have one you CANNOT eliminate that possability. – Ramhound May 17 '13 at 12:53
I do not have a cpu fan/heatsink at the moment

If you're seriously running a i7 3930k without any heatsink, just stop searching.

It has a max TDP of 130 W and cannot run even for a few minutes without any cooling system. The heat exchange surface of a CPU is really really small and even if the actual TDP is not that high, it won't be enough to prevent a continuous increase of temperature.

If the CPU reaches a dangerous temperature, it will either shut down itself, be shut down by the BIOS temperature sensor or begin to make miscalculations causing the OS to crash (usually BSOD on Windows).

You have two ways to check if high-temperature is the cause of your random shutdown :

  • Put one finger on the CPU and wait until it starts smelling bacon
  • Use a tool such as RealTemp to check the Thermal Status Log (as suggested by @Hennes)

But if you can't manage to fully boot your computer, you may be stuck with the first option.

Conclusion: Don't run a desktop CPU (especially a high-end one) without any cooling system, unless you want to cook something.

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True for older CPU's. On a modern i7 the CPU will pull the PROCHOT line when it gets to hot. From a user perpective that is the same as a hang or power down, depending on the motherboards design. Regardless of the design, the CPU will disable itself. – Hennes May 17 '13 at 13:54
+1. Cpus get real hot real quick. They need heat sinks. – Michael May 17 '13 at 13:57
Note that you can check if if prochot was the reason for the previous shutdown. See page 14-14 of Intel® 64 and IA-32 Architectures software developer’s manual. From the same manual, please note that “the recommended response to this condition is a system shutdown”. – Hennes May 17 '13 at 14:04

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