Shutdown system on Abit boards when overclocked too high?

So far I have seen this problem on an IS7-E and AI7. Both are relatively recent boards I purchased in the last six months. It also happened on a DFI LanParty 875P. When I overclock a 2.8C or 3.0C up above 1.675 actual VCORE (usually at around 3.8+ gig or so), the system shuts down - Boom! There is no power to the system. I have to turn off the power switch then turn it on for the ON switch on the computer to work. It happens as soon as I stress the system: running Sandra Arith, Aquamark, 3DMark2001, PCMark2002. If I keep VCORE under 1.675 the problem goes away.

So far this has happened with 8-10 CPUs, however it does not happen with Golden chips. I have a 3.2C that does 245 fsb or 3.92 gig at default voltage (haven't tested higher) and it doesn't happen here. Or with a 3.0C I have that does 260 fsb or 3.9 gig @ 1.55 VCORE. But maybe these CPUs are so damn good I can hit high overclocks without having to use anything near 1.675 volts!

I have tried reseating the CPUs, checking the AS3. I have disabled all temp/CPU monitoring in the BIOSs. It's not overheating as I am watercooled and the CPUs never run over 40C (digital temp probe).

I am POSITIVE there is an overclock limiter on the later Abit, and possibly DFI boards that shuts it down when the CPU is stressed. I do not have this problem on Asus boards.

Anybody else experience anything similar?

This could be the power supply shutting down due to overload. That .125V difference could add 10-15 more watts to the 12V load. What is the power supply 12V Amp rating?

There is no overclock limiter on ABIT boards.... since you left out your PSU you might want to look there first.... the 12v rail is the most important now with highly loaded and overclocked systems.... Rich_L the addational Watts is not what you need to look at its the AMPs being pulled by the cpu when being stressed at the higher speed and increased cpu Voltage....

Evilsizer said:

There is no overclock limiter on ABIT boards.... since you left out your PSU you might want to look there first.... the 12v rail is the most important now with highly loaded and overclocked systems.... Rich_L the addational Watts is not what you need to look at its the AMPs being pulled by the cpu when being stressed at the higher speed and increased cpu Voltage....

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Well, I agree with this now . Last night I replaced the AI7 with a P4C800-D - same problem! It was clear now the problem has been getting worse and it had to be the PSU. Sure enough, I put in new Fortron 530W unit and the problem went away totally. What was deceiving is I had the pots bumped on the bad unit (Sparkle 400W), and rails all looked good and overvolted. But it must be an overcurrent protection or short circuit prevention feature on a failing unit. I have no complaints: the unit has served me faithfully on severe overclocks for about two years now.

Another Sparkle unit crapped out on me after 3 months use, as I bumped the pots on that one even more. I no longer bump pots anymore for this reason. While the voltages were well below the max allowed, I believe it shortens the life of the units. Moreover, I could not overclock my CPU/ram any higher with the bumped pots.

BTW, I'm impressed with this Fortron unit. My rails are running 3.3, 5.11, 11.98-12.04. You think so what, about dead on. Well I am running a 3.0C overclocked to 3.9 gig at 1.674 VCORE, 1.8 VAGP, Vitesta PC4000 at 1:1, 3-4-4-7 @ 2.75 volts, two 120-mm fans, 3-80 mm fans, 2-50 mm fans blowing on the mosfets, and a 40 mm fan on the NB, plus a Corsair HC200 with it's 120 mm fan in tow. The 3-120 mm fans are whopping 0.55 amp units. And imagine the wattage that 3.0C at 3.9 gig is sapping! I am running a 9800XT Pro @ 440/385 too.

Before the PSU change I tested three Q401Axxx 3.0Cs: one did 3.9 gig @ 1.55 volts, the other two 3.765 @ 1.675. With the Fortron unit, the two bad ones now do 3.9 gig @ 1.675 and 3.81 gig @ 1.675 - no shutdown when stressed. Hell, I did not test the good one that did 3.9 gig @ 1.55 volts on a failing PSU!

then give me one of those 3.0c @ 3.9 with 1.55v

One's going in a Vapochill BTW .

I can attest to the good power regulation of the Abit boards, even an AI7. I heard the bad rap on the AI7 - that the 865P boards don't have the balls of the 875P boards like the IC7 and MaxIII. When I had the bad PSU in, I could boot Windows OK at 3.9 gig with the AI7, 'cept the system would cut out when starting 3D. I swapped in the P4C800-D and at same overclock, I couldn't even boot Windows!