prime95 detected errors

[gareth170]

hi

im got another problem now. i've ran prime95 just now 3 times on in-plaace-large FFT and it detected an error even when everything is at stock. the first time worker#2 stoped then second time worker#4 stoped, then 3rd time worker#2,3 stoped.

it can't be the cpu can it? i don't get blue screens or windows errors

 

[gareth170]

it looks like heat issue, i think. when it gets to 40-41c it seems to fail.

any ideas?

 

[gareth170]

i did a on blend and small fft for 25min and it was fine over 40c. on in-plaace-large FFT it failed at 40+c after about 2-5min.

i've ran memtest and the sticks seem fine.

is it nothing to worry about??

 

[gareth170]

ran memtest for 8hours..

what i don't understand is its fine below 40c on in-plaace-large FFT even for 10-15min but as soon as it goes to 40+c it fails.

 

[gareth170]

Run the Intel burn test for 2 hours, 3000Mb +, if your system is that unstable it will bluescreen almost instantly.

does that program run with amd cpu's?

There are so many prime95 versions, some crash (illegal operation) or simply give false errors I would ignore it.

i was thinking this. prime95 is a windows app and we know sometimes windows apps can errors or make fake errors.

a dos version of prime95 would be much better.

anyway i will try underclock the cpu then if that works its the cpu, but if it still fails then it can't be the cpu, right?

 

[gareth170]

well underclocked it to 2.5ghz and i tested it for 20min which worked fine. put it back to 3ghz and tested it again it failed in 5min.

 

[gareth170]

May be worth checking your motherboard isn't undervolting your cpu.
Manually set this to the stock voltage in the bios, then retest.
And the 40C temp limit you've found is very odd, what program is giving those readings?

amd overdrive says vcore is at 1.35v which is right, cpu-z says 1.328v. my bios haven't got vcore option, only has "cpu vid special add" which add on to the vcore default voltage.

i've used amd overdrive, EVEREST Ultimate Edition, coretemp, all 3 say the same temps

 

[gareth170]

well now i've underclocked my memory to 800mhz it seems to be working at 3ghz..

why did it work when i underclocked the cpu to 2.5ghz and ram was still at 1066miz?

 

[gareth170]

i bumped up the ram voltage to 2.11v which in real world it 2.1v and put it back to 1066 but still fails.

it seems to only like it when i underclocked my memory to 800mhz and cpu at 3ghz or underclocked the cpu to 2.5ghz and ram 1066miz..

 

[gareth170]

update:

i have changed the ram mode from ganged to Unganged, and it's seems to of fixed it. i ran prime95 for 27min on 1066, 3ghz it was fine then i upped the cpu to 3.4ghz and ran prime95 for another 27min and that was fine..

on monday i changed the ram mode to ganged because i read that ganged = dual channel, but since i've read more about it , ganged = x1 128bit, unganged = x2 64bit. phenoms have 2 separate 64bit channels.

 

[gareth170]

yeah i know i should leave it running over night but tbh i don't keep the system on 24/7. because of the electric bill is so high. i'm already using it from about 9am in the morning till about 12.30-1am at night everyday lol. so if it wasn't stable i would see a crash or something within that time.

 

[gareth170]

A minor instability might not cause a crash though, for a gaming system it could be as minor as a slight distortion in sound (a pop or a crackle), a pixel out of place, something so minor that you could miss it. Prime95 doesnt crash, it simply detects that the math doesnt add up. That said instability on a gaming system might cost you in FPS as well. There was a recent Aandtech review of i7/Phenom 2/Q9550 where in a few tests the over clocked i7 was actually slower than the stock speed chip that was over 1ghz lower clock rate, something causing instability imho.

If you were using your computer to perform accountancy services for example, it wouldnt look too good if your computer was getting the math wrong, but for a gaming system sometimes stable enough is good enough.

By the time a computer actually starts crashing its probably making multiple errors. Anyway as long as its stable enough for your needs.. Enjoy

i've ran Prime95 about 6-7 times before when it was on ganged and it did detect a error and also crash in Prime95 but now on unganged i've ran Prime95 for over a hour and it didn't find any problems.