Unstable system on stock settings.


Mar 3, 2010
I have a homebuild gaming PC with the following specification:

- Intel Core i5 750
- ASUS P7H57D-V EVO Motherboard
- Crucial Ballistix DDR3 1333MHz 2x2GB
- HIS ATi 5770 1GB
- Samsung 1TB Spinpoint F3
- Windows 7 64bit/ Linux Mint 32bit

Now, for quite a while I've been having problems with determining the cause of this problem.

Sometimes, usually during games, the system will either freeze or display a BSOD. The system also crushes under Linux too, but a lot less often.

So, guessing the CPU might be the culprit, I used CPU stress software to test the stability of the CPU (The CPU is on stock settings and voltage set in the middle of official voltage range)

IntelBurnTest: Usually results in an unstable error.
Prime95: Sometimes get a "FATAL ERROR: Rounding was 0.5, expected less than 0.4"

I contacted Intel Support about this issue, they said that in order to RMA the CPU, it would need to fail the Intel Processor Diagnostic software.

I tested using this software, the result was a Pass on all the times I tested with it.

So I then went to test the RAM. I first tested with both sticks and out of 15 tests there was a few errors that occurred on only one test and the memory addresses were all close to each other. I then proceeded to test each stick for quite a while (Long enough one time that it managed to do 75 tests) and each came up with no errors, I then tested both sticks together again, but this time there was no errors.

The RAM timings are set correct and the voltage is manually set to 1.65V (as stated on the sticks themselves) as the mobo was only supplying 1.2V.

I then went back to testing the CPU with IntelBurnTest. I left it and when I came back later, I was greeted with this:

What I want to find out is, which is the faulty part (CPU, RAM or Mobo?) so I can RMA the right part.
Ram is funky, the actual errors from memtest arent useful for diagnosing anything nor are the locations, primarily because you shouldnt get any errors from memtest. Run it for 5 full passes and if you have any errors you should RMA the RAM its just going to be the random pain in your ass until you do.