Computer randomly shutting down

Hi everyone
So my computer randomly shut down without any warning. This is the third time its happened. It pretty much freezes, makes a buzzing noise and turns off. I got a 5 month old system. I got my processor at 4.0 GHz with 1.4 Volts. I got good ventilation, HAF 922. My other specs are GTX 275, 4GB of Kingston Hyper X RAM, a 750 GB SeaGate hard drive.

Thanks everyone.

What is your PSU and motherboard spec?

Hmm. You have enough power. How did you test for the stability of your overclock?

Another possibility is your GPU dying. Try it in another system and see if you have the same issue.

-CPU not capable of running at that high a clock speed stably
-RAM not capable or running at the overclocked frequency
-Other component not capable of the overclocked speed.

The latter two can be solved by lowering the multiplier on those components. Until they become stable.

If you asking why the CPU cannot physically run stable at such a frequency, we get into computer engineering. I think at a higher frequency than the chip can take, the CPU will miss clock cycles when trying to transfer data. It becomes more unstable the higher you get because it misses more. This is why to ensure complete stability, you have to run stability tests for extended periods of many hours. The longer the better. I run prime95 for at least 12 hours and linx I set to use 2GB of memory and run for something like 50 runs. I run both programs at different times, of course.

How did you test for stability a month ago? Stability shouldn't change unless you changed a component in your system. Or if it is running at a hotter temperature than it was a month ago.

CPU's do seem to degrade with age if they are overclocked at their maximum. Sometimes the solution is to decrease the overclock slightly. Other causes could be capacitors in your power supply or motherboard not being as good as they were when new. Replacement of the power supply might enable you to get back to the original overclock.

Anyone have any other thoughts on this?