Prime stable not game stable?

[Disco_stoo]

A little question as my PeeCee is behaving oddly. Recently upgraded and went with a ASUS sli prem, and AMD 3700 cpu with a freezer pro stuck on top. Overclocked it to 2.7ghz quite happily and was getting about42 degrees heat under load.
It was prime 95 stable for about 12 hours (longest I was able to run the test - but did this a few times and never got an error).
Played oblivion happily and did a fare bit of benching with 3d mark 05 and 06.

Anyway, tried the HMM 5 demo and it crashed every 5 minutes (literally) and Dawn of War was also crashing (which it had never done before). tried changing drivers from omega 6.3's to cat's then the cat 6.4s to no avail.
Then I put the cpu back at stop and all of a sudden crashes stopped. the problem is I don't know how far I can clock cos Prime 95 thinks it's fine at 2.7, and even oblivion seems happy at that speed, whereas DoW and HMM5 can't stand it. All sounds a bit odd to me, I'm confused. Help?

 

[Teknodeamon]

what mem u got?

 

[Corasik]

I believe that Prime95 uses the ALU, and FPU in the processor, but doesnt make use of SSE/2/3, MMX, or 3DNOW. So any stress testing of an overclocked processor, is limited to the ALU, and FPU (Plus of course the prefetch unit, the decoders, the pipeline and the cache memory).

It does also stress test the motherboard, and memory subsystems, which is a good thing, so its well worth Prime95 stress testing a system. But its certainly not a guarantee that every transistor in the CPU is working correctly.

If your HMM5 demo is crashing every 5 minutes, then you could always add this into your test suite when overclocking. Gradually lowering your cpu speed(or increasing VCore) until HMM5 is stable as well as Prime95.

 

[Disco_stoo]

Tekno - it's 2 x 512 corsair twinx

Corasik, you're quite right, HMM5 crashes so consistently it would be quite a useful one to use to test the set-up.
Thanks for the info about what prime 965 does. I'd thought I was going mad. Odd how 3d mark and oblivion seem uneffected.

 

[Corasik]

Yeah, Oblivion is normally quite fussy when it comes to overclocking, but I dont know of any application that tests every possible cpu instruction... mebee your chip is just making 1 tiny mistake somewhere, and its showing up with the HMM5 demo.

I thought my P4 was 100% stable at 3.6Ghz, ran everything, Prime95, Memtest, dozens of games, no problem. Until I tried to install a mid 90's game Age of Empires (number one).. Bombed out during the install routine!

 

[marc2003]

i had stability problems with gta:sa even though it was 11 hours prime stable. a slight vcore increase fixed my problem.

 

[daftVader]

i had stability problems with gta:sa even though it was 11 hours prime stable. a slight vcore increase fixed my problem.

Same was true for me. Was Prime stable but games like Quake were crashing out. Bumped up the vcore by one notch and everything ran perfectly.