Prime95 Problem?

[imported_OmegaZero]

I am attempting to use Prime95 to test my new rig. I have run one instance without error for 12 hours, at which point I stopped it. However the documentation says I should run two copies simultaneously because I have a hyper threading P4. This is where I start to have issues (I think) ...

When two copies of the program are running one of the two will fall to 1%-5% CPU usage, leaving the CPU at approximately %75 instead of 100%. I have tried setting both instances to high priority, but it still happens. Is this an error? Does this mean I have a problem, even though neither instance shows an error? How can I fix it?

 

[Shimmishim]

what version of prime you running?

and what test you running?

 

[SrGuapo]

Are you sure HT is enabled?

 

[imported_OmegaZero]

Hyper threading is definitly enabled (according to CPUz & PCMark). Version of Prime95 is 23.8.1, test is "Torture Test - Blend" w/1500MB RAM. I have tried it with 8MB, 128MB, and 500MB also. All work perfectly in one instance but the second still drops to 1%-5%.

I tried SP2004 (another version of Prime95) because it is supposed to have more verbose error reporting, but I got the same result: No error, just a drop in CPU usage of the second instance.

CPU Burn-In 1.01 (x4 for 6 hours), PCMark04, 3DMark03, and 3DMark05 all run without error.

Is this an OS/software problem, a hardware problem; is it a problem at all?

I hope I can get this sorted out. My benchmarks were great other than this issue...

 

[Shimmishim]

you are supposed to run small fft's to test your cpu not blend test.

small fft will keep your cpu at 100%