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prime95 detected errors

Soldato
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24 Jan 2007
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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
 
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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??
 
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It fails because your computer is unable to perform "simple" math. If it fails Prime95, its not stable period. Failing in 2-5 minutes is definalty not stable.

How long did you run memtest for, 12 hours minimum imho, if memtest passes and Prime doesnt, then there's a problem with the motherboard or CPU.

It's worth worrying about it. You should be able to run prime for a week nonstop and still have zero errors.

If your only using your computer for gaming, and it doesnt crash in the games you have then you might choose to ignore it, but as soon as there's a crash will you blame a game, windows, or remember your PC fails prime.
 
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.
 
I agree with Corasik, if you've ruled out memory (a solid 12 hour wall test) and possible overheating issues, then the processor is more than likely defective. If you can return it i'd do so and state it fails prime and send them a screenshot too.
 
Run the Intel burn test for 2 hours, 3000Mb +, if your system is that unstable it will bluescreen almost instantly.
There are so many prime95 versions, some crash (illegal operation) or simply give false errors I would ignore it.
 
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?
 
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?
 
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
 
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?
 
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..
 
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.
 
Ganged V Unganged. Both work on AM2+ / AM3 cpus. With ganged as you say its configured as a single 128bit wide controller, but only 1 core can access memory at a time, any requests from other cores are placed in a queue and serviced as soon as possible. For single core applications this can offer a slightly better performance

Unganged, 2x64bit, two cores can access memory at the same time giving better multitasking performance. If 3+ cores need concurrent memory access they are queued as with ganged mode.

Sounds like there is a slight issue with your board/cpu (might just be a bios issue) but if it runs reliably in unganged mode, I cant see any reason why you shouldnt just stick with unganged. Windows is multitasking all the time to some degree, so it should offer a well balanced performance anyway.

I'd leave it running over a few nights, just to make sure it doesnt pop up with anything, I had an old P4 chip which would fail after 16 hours and a few minutes of prime95. Was stable with most the games I had at the time, but later I did find games which were unstable... Fix for that computer was reduce the fsb overclock by 1mhz. (Yep 275x12 unstable @16 hours, 274 stable for 30+ hours)

Anyway, ive gone OT now :) Glad you found a workaround for the problem. Sounds like a good option.
 
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.
 
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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
 
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.
 
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