System refuses to oc past a certain point: cpu or mb problem?

[Electrode]

Hey all. I've been having this problem for months now, and I want to know how to fix it.

I have an MSI 694D Pro-AR motherboard with 2 Pentium 3 667MHz CPUs. For some reason, I can only get it to run up to a 147 MHz bus speed, which comes out to 735 MHz CPU speed. Any higher, and it won't boot. No vga bios, no post, not even hd spinup.
With my ASUS CUSL2 motherboard and one of the above mentioned CPUs, I could go all the way up to 800 MHz (160 bus) before losing stability, and it ALWAYS booted.

Now, what I'm wondering is, what's wrong? Is it a known limitation of the motherboard, or do I have a bad one that needs to be RMA'd? Is one of the CPUs bad?

Complete roundup:
MSI 694D Pro-AR motherboard (MS-6321)
768 megs PC133
2 Pentium 3 coppermines, 667 MHz
Mini Copper Orb hsf's (avg. temp: 43 degrees)
Gainward Cardexpert Geforce3 Powerpack !!! (no vivo)

 

[AndyHui]

Timings and other variables are always more sensitive in a dual CPU environment. Are you sure that both processors can handle that sort of overclocked speed? Remember that the probabilities double when you have two processors.

Ideally, check that the other processor works at 800MHz as well. You bought a 667 processor. You cannot return the processor and claim that it is bad simply because it will not operate at a speed higher than what it is rated at. You should always keep in mind that speeds are not guaranteed when you overclock, so I highly doubt that you can blame the motherboard and claim an RMA.

 

[Electrode]

well, if I get a chance I'll take the CPUs out and test them individually in one of my uniprocessor rigs.

But the thing that really has me confused is, why would it work perfectly at one speed, but not at all just 5 MHz (bus) higher? Shouldn't I see instability first?

 

[AndyHui]

Not necessarily. There are points where it will just cut out completely.

Certainly for dual processor systems where stability is a concern, I think it is more beneficial (where you may be running something important) for the system not to work at all rather than run unstably and corrupt your work.