How can Prime95 report errors but my system be 100% stable?

[OS]

Originally posted by: apoppin
All I am suggesting is that you downclock your system to default and run Prime95 over night.

IF it fails . . . perhaps there is some problem with Prime95, it's installation or some other flaw in your system - that would tend to substantiate your claim.

On the OTHER hand - if your default system runs Prime95 flawlessly - there just might be something wong with YOUR theory and your O/C'd system.

Personally, I believe you have already made your mind up that your system is "stable" and would find it hard to accept "evidence" to the contrary.

I think you should just let him figure it out for himself. He eventually will if he doesn't want to listen. :Q

 

[JavaMomma]

I always test my systems with Prime95 when overclocking.
Right now running a 1800+ at 1833Mhz (tested here for 72 hours)
It can go higher to 1910Mhz but Prime95 errors out after about 6-8 hours...so i backed off.

I think it seems like a pretty decent test to me, I mean obviously if your computer cant do the calculations something is wrong.
I'm sure other software can stress your system like that.

I love how when I turn Prime95 on I can hear the fans in the system change pitch. I guess the Powersupply is being stressed also under the load.

 

[apoppin]

Originally posted by: OS

Originally posted by: apoppin
All I am suggesting is that you downclock your system to default and run Prime95 over night.

IF it fails . . . perhaps there is some problem with Prime95, it's installation or some other flaw in your system - that would tend to substantiate your claim.

On the OTHER hand - if your default system runs Prime95 flawlessly - there just might be something wong with YOUR theory and your O/C'd system.

Personally, I believe you have already made your mind up that your system is "stable" and would find it hard to accept "evidence" to the contrary.

I think you should just let him figure it out for himself. He eventually will if he doesn't want to listen. :Q

Well, I presented it as a kind of a "challenge" - hoping not to be too obviously impolite. You "caught me" so I guess I failed.

 

[BmXStuD]

Because. ur pc is not stable i guess. LAST NIGHT I RAN PRIME 95 AND ANOTHER STRESS TEST AND MY PC PASSED W/ BOTH GOING! Now my pc is stable, and maybe something it will hard lock in games, but not anymore.

 

[OS]

Originally posted by: apoppin
Well, I presented it as a kind of a "challenge" - hoping not to be too obviously impolite. You "caught me" so I guess I failed.

Nah, I wasn't trying to call you out or anything. It's just this is the sort of thing that he'll find out about one way or another. :Q

I mean, it doesn't really get any more clear than "hardware failure detected" :Q

 

[apoppin]

Originally posted by: OS

Originally posted by: apoppin
Well, I presented it as a kind of a "challenge" - hoping not to be too obviously impolite. You "caught me" so I guess I failed.

Nah, I wasn't trying to call you out or anything. It's just this is the sort of thing that he'll find out about one way or another. :Q

I mean, it doesn't really get any more clear than "hardware failure detected" :Q

It's pretty clear.

EDIT: I'd also suggest anyone interested, doing a "search" in GH and O/C'ing - even theough the archives - on "Prime95" . . . there was some "heavyweight" discussion from time-to-time that would provide the "details" and causes of P95 "failures".

 

[Duvie]

OS...did he say somewhere that I am missing that it was a "hardware failure detected"??? I am waiting for that clarification...I look at it this way rounding error....It just didn't do it right, it didn't get the job done and as apoppin stated if it runs fine at a lower speed but everything the same shows it is realted to the increased speed of the chip...

 

[apoppin]

ALSO MAKE SURE YOUR pRIME 95 IS UP-TO-DATE!!!

From a quick search of current threads using the keyword: Prime

The problem might not be your machine, but an older version of prime 95.

If you go to prime 95's revision history, you'll see that a number of changes were made in versions 22.2-22.6 to correct bugs that created erroneous errors. In particular, versions 22.2 and 22.3 have revisions made because "version 21 was too aggressive in choosing FFT sizes for the P4."

 

[OS]

Originally posted by: Duvie
OS...did he say somewhere that I am missing that it was a "hardware failure detected"??? I am waiting for that clarification...I look at it this way rounding error....It just didn't do it right, it didn't get the job done and as apoppin stated if it runs fine at a lower speed but everything the same shows it is realted to the increased speed of the chip...

He didn't say it flat out, but it's the message prime95 gives when it finds an error.

Yeah I know right about where the errors start rolling in from overclocks on my computer.

 

[Duvie]

what abour rounding error...you have never seen that one??? that is the one I encounter when I oc too high...I only a few times seen the other and I cleared up with memory timings and such...

 

[flexy]

honestly, i rather prefer a system i know the cpu calculates right than adding another 1% of overclock speed with the knowledge that my cpu internally cannot tell apples from pears

It's just a weird feeling seeing prime reporting that the cpu just calculated something 'wrong'...i mean, what do i have a pc for when i cant trus't the cpu's function ? (Yeah, you're right....Seti Units just as one example...)

greets

 

[fr]

I haven't used Prime95 in years, but I tried the newest version tonight and got the following error:

FATAL ERROR: Resulting sum was x.xxxxxxxxxxxxxx+26, expected: x.xxxxxxxxxxxxxx+26



Those x.xxxxxxxxxxxxxx numbers are exactly the same. The error must have been in the +26 digits.

 

[oldfart]

From the Prime95 stress.txt readme file:

CAN I IGNORE THE PROBLEM?
-------------------------

Ignoring the problem is a matter of personal preference. There are
two schools of thought on this subject.

It is likely that most programs you run will not stress your computer
enough to cause a wrong result or system crash. A few games stress your
machine and a system crash could result. Stay away from distributed
computing projects where an incorrect calculation might cause you to
return wrong results. You are not helping these projects by returning
bad data! In conclusion, if you are comfortable with a small risk of
an occasional system crash then feel free to live a little dangerously!

The second school of thought is, "Why run a stress test if you are going
to ignore the results?" These people want a guaranteed 100% rock solid
machine. Passing these stability tests gives them the ability to run
any program with confidence.

 

[Eug]

I haven't run Prime95 in a while, but IMO Prime95 alone isn't good enough.

This was rare I'll admit, but on an extremely overclocked system, I could get Prime95 to run without error, until I threw even more tough stuff at the computer.

ie. Prime95 would run fine, but Prime95 with Unreal Tournament intro flyby simultaneously would cause a problem. At default speed (for both the CPU and the GPU), it would run fine. Turn down the GPU speed and keep the CPU overclocked, and I'd still have problems with Prime95. Dunno why exactly, but I wonder if it was partially due to case temps. Thus I would declare the system to be unstable, despite the fact that basically everything I ran in real life was "stable". Back down the overclocking on the CPU, and Prime95 would be fine. (Despite the fact that these programs are supposed to work only at idle, adding it stresses the computer more than a 3D game alone. Indeed, if you benchmark a game with OGR for instance running in the background, there are small but significant consistent slowdowns with FPS rates.)

My fave was when my friend tried to convince me his overclocked system was stable, because he had been running that config for 2 years. He said he was fine even playing games, although I did note that every once in a while he'd have strange problems with a few games. Any 2D stuff (eg. mail, word processing), was 100% fine however. I finally convinced him to run Prime95. Guess what? Prime95 reported errors. Backed down the speed, and no more problems with Prime95.

My philosphy for overclocking: Assuming there isn't a problem with the software, run the most hardcore series of burn-in tests you can find (which at the time for me was running several CPU and memory tests individually, then simultaneously, and then a CPU test with a 3D game loop) until I got to a level of 100% stability. Then I'd back down the speed a couple of notches. In other words, if I my CPU can do all I throw at it at 25% overclocked (but not 26% overclocked), then I'd consider running it at 15% overclocked.

All that said, I dunno how reliable the current version of Prime95 is with current hardware. I am not excluding the possibility that there might be a bug or incompatibility somewhere. However, I suspect the system in question here may simply be unstable, by my definition. If so, I would not trust my data to such a computer.

 

[ssanches]

I'm more concered with getting an answer to EXACTLY what happens when Prime95 fails and why it's an indicator of a problem when nothing else in the system fails.

Here's something from the Prime95 FAQ's . I guess some folks need to read it

Q) My machine is not overclocked. If I'm getting an error, then there must be a bug in the program, right?
A) Unfortunately, no. The torture test is comparing your machines results against KNOWN CORRECT RESULTS. If your machine cannot generate correct results, you have a hardware problem.

Q) Prime95 reports errors during the torture test, but other stability tests don't. Do I have a problem?
A) Yes, you've reached the point where your machine has been pushed just beyond its limits. Follow the recommendations above to make your machine 100% stable or decide to live with a machine that could have problems in rare circumstances.

Q) A forum member said, "Don't bother with prime95, it always pukes on me, and my system is stable!? What do you make of that?
Or
We had a server at work that ran for 2 MONTHS straight, without a reboot I installed Prime95 on it and ran it - a couple minutes later I get an error. You are going to tell me that the server wasn't stable?
A) These users obviously do not subscribe to the 100% rock solid school of thought. THEIR MACHINES DO HAVE HARDWARE PROBLEMS. But since they are not presently running any programs that reveal the hardware problem, the machines are quite stable. As long as these machines never run a program that uncovers the hardware problem, then the machines will continue to be stable.

 

[XBoxLPU]

My machine is stable at 10 X 180 but fails Prime 95 within a min..

@ 180 X 9.5 Prime 95 has been running over 24 hours.

 

[apoppin]

Originally posted by: XBoxLPU
My machine is stable at 10 X 180 but fails Prime 95 within a min..

In this case, "stable" and "P95 Fails" is an OXYmoron.

@ 180 X 9.5 Prime 95 has been running over 24 hours.

"Stable" (or more stable).

 

[XBoxLPU]

Originally posted by: apoppin

Originally posted by: XBoxLPU
My machine is stable at 10 X 180 but fails Prime 95 within a min..

In this case, "stable" and "P95 Fails" is an OXYmoron.

@ 180 X 9.5 Prime 95 has been running over 24 hours.

"Stable" (or more stable).

At 10 X 180 my pc will not crash, as others have mentioned it apps will not close and give errors. No BSODs.. everything is " stable" IMO

but I am running at 9.5 X 180 now. No crashes of course and prime 95 still hasn't failed

 

[human2k]

So whats stability again?

 

[ProviaFan]

Originally posted by: XBoxLPU

Originally posted by: apoppin

Originally posted by: XBoxLPU
My machine is stable at 10 X 180 but fails Prime 95 within a min..

In this case, "stable" and "P95 Fails" is an OXYmoron.

@ 180 X 9.5 Prime 95 has been running over 24 hours.

"Stable" (or more stable).

At 10 X 180 my pc will not crash, as others have mentioned it apps will not close and give errors. No BSODs.. everything is " stable" IMO

but I am running at 9.5 X 180 now. No crashes of course and prime 95 still hasn't failed

Please, people, get your definition of stable right for once. It's not stable if it can't calculate correctly, regardless of whether or not it crashes with a BSOD at times. Yes, it may appear to run Word, Outlook, and IE (or even Photoshop or 3dsmax) fine, but if there is any anomality with the results it returns in any calculation (aka Prime95), it is not stable. It may be stable enough for you, but again, it is NOT stable.

My Athlon XP 1700+ (12.5*157FSB) can only run Prime95 for about 5 hours before reporing a mysterious "This program has generated an error and must be shut down" dialog from Windows. I've not tried backing down on the overclocking yet because I've been running for over 9 days now with no problems in other applications. This is definitely "stable enough for me" but that still doesn't make it "stable."

 

[Sahakiel]

IMO, nobody should be commenting on whether Prime95 is BS or not until he/she can design, simulate, and verify a simple CPU core design. aka bloody well understand just exactly how a processor works.

 

[flexy]

when i tune my overclock, fsb and mem timings, i do:

1) get memtest and run it to verify that the system reads/writes to/from memory correnctly
if this passes:
2) get prime and run it for a while
if prime fails, more tweaking, eg. FSB back a notch and/or cpu voltage up

I had no problems whatsoever with this methods..and i *might* say when these two tests pass i can assume a pretty stable machine

There might be three schools of people:

1) "I do NOT overclock my cpu, nononono"
2) "I overclock, but i want a stable and reliable PC"
3) "I overclock and try to squeeze every bit out of my machine, and i dont care as long as i can game fine or my fav. app runs fine"

I prefer 2) since it is a good compromise, imh.

 

[apoppin]

Originally posted by: Sahakiel
IMO, nobody should be commenting on whether Prime95 is BS or not until he/she can design, simulate, and verify a simple CPU core design. aka bloody well understand just exactly how a processor works.

The people who evidently DO understand it, say Prime 95 is not BS - although it should be used together with other tests that your system is stable.

The people who "understand it" also say if your system generates errors in P 95 it is NOT stable (no matter what your "opinion" of your system is).

Do a "search" . . . I am really jammed up busy today.

 

[OS]

Originally posted by: Sahakiel
IMO, nobody should be commenting on whether Prime95 is BS or not until he/she can design, simulate, and verify a simple CPU core design. aka bloody well understand just exactly how a processor works.

hahaha, that's actually a project I'm working on right now.

I'd have to say though, one doesn't really need that level of education to understand that if errors in any application go away when you reduce the overclock, that your excess overclocking is causing some problems, regardless of how latent the problems are.

 

[merlocka]

I wonder if the people who think their PC's are stable (even when failing P95) are the same ones who tell you that XXX brand hardware is the best because "my computer hasn't crashed in 8 days". (Dude, if it's windows it crashes once a month just for the hell of it).

If Prime95 comes up with errors, your OC'd too high.

Just because you don't mind rebooting doesn't mean that you can redefine "stability".