Which bit is busted?

[MURDEROUS G]

Recently built a GA-P35-DS3P, Q6600, 4GB OCZ 800MHz RAM. The system is basically just not stable no matter what I do. At first I tried some pretty mild overclocks (3GHz @ 333x9, 2.8GHz @ 400x7) and the system would almost immediately freeze when I tried a 'In-place Large FFTs' or 'Blend' torture test on Prime95. The 'Small FFTs' test in comparison seems to be stable up to 3.2GHz (haven't tried it higher than that).

I was advised to give the RAM a going over to make sure that it was OK. So (I apologise for the very poor picture quality, they were taken with a laptop webcam)...

First I tested one 2GB stick in memtest86+:

Wow, 524 errors?? I googled the errors and found that the DS3 boards sometimes give '__feedf18' false positives in memtest.

I test the same RAM in the same rig with Windows Memory Diagnostic:

Lots of errors again, but the same errors.

I take a stick of 1GB RAM from my old machine, which I know to be good, and test it in the DS3P:

Loads of errors, and yet again they are _feedf18 ones. Hmmm.

Just to make doubly sure, I take one of the 2GB OCZ sticks, and test it in my old rig:

That pretty much settles it, then. I guess the RAM is fine and the DS3P is just giving me false positives (at least I assume that's what all the errors are from the RAM tests on the DS3P...?).

Discounting the RAM for now, I played around with the FSB and multi to see if I could find any combination that was actually stable, but it doesn't seem like there is one. I've underclocked the ******* system significantly with no success - I've tested it at 2GHz 333x6 and 2.1GHz 266x8 and it still fails within minutes.

So, to conclude, something is wrong with my system, but what? I'm damn sure I need to RMA something, but I'm not experienced enough with hardware to actually deduce what it is. Can anybody put all of the above together and come up with a plausible answer? If I have left out any information which might be helpful, please let me know.

Thanks,
mg

 

[Cob]

Have you tested each of the slots?

 

[MURDEROUS G]

Hi Cob,

Thanks for the reply.

Have you tested each of the slots?

I hadn't thought to, actually. Up till now the RAM has been either in 1+3, or when I'm testing sticks singly, just 1.

I've just put one of the 2GB sticks in the second slot and am testing now in Prime95 at 3GHz 333x9. It has has remained stable for about half an hour so far (previously it would usually crash within 10-15 seconds). Are the memory slots to blame?

 

[Pneumonic]

OK just to cover some basics

a) you are running 4 sticks of RAM has issues but not with 2 stick have you up'd the northbridge voltage a little?

b) is you RAM running at the correct voltage? most boards default to 1.8v your RAM needs more to run stable

 

[MURDEROUS G]

a) you are running 4 sticks of RAM has issues but not with 2 stick have you up'd the northbridge voltage a little?

No, I'm running two 2GB sticks, not four. That aside, I've tried leaving the NB voltage at stock and upping it manually but the instability remains.

b) is you RAM running at the correct voltage? most boards default to 1.8v your RAM needs more to run stable

Yeah, the RAM is at +.3V in the BIOS overvoltage settings.

 

[Cob]

Certainly sounds like a dodgy slot.

 

[Pneumonic]

ok next question

I take it you are running both dimms in channel A or both in channel B have you tried them in the other channel? i.e. running both in A move them both to B

Ninja Edit!:
Would agre with Mr Cob