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The Prime 95 fallacy

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Frankly, it could be anything. The problem may manifest itself in many forms. The P4 I used to be own was stable in everything I threw at it, except for Prime95. I ended up getting corrupted data when downloading stuff from websites, and the data corruption got worse the larger the file. For the longest time I was convinced that either the coaxial cable from the main pipe to my modem was faulty, or that the main pipe was faulty, but I found out later that it was coz of my overclocking. It's an obscure example, but it shows you how stuff like this can hurt you if you're in denial like I was.

Cheers.
 
Originally posted by: flawlssdistortn
Do you think it's possible for a system that's not prime95 stable to corrupt files that it's downloading or installing?
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Yes, it could be having random calculation and/or memory errors as well if it is failing prime, though as mentioned earlier prime95 itself is more FPU intensive and downloading files probably doesn't touch the FPU much if at all.
 
Plus when you run it on WinXP SP2 (with Data Execution Prevention) you get the following message:

"To help protect your computer, Windows has closed this program."

Hmm, maybe they know something we don't? 😉 Prime95 IS A VIRUS! Flames on a postcard please. 🙂

My 2.2GHz 3200+ runs fine @ 2.5GHz, except when it doesn't. No biggie, my games don't seem to crash at all. The odd time it gets a bit weird on boot. Programs don't crash on me at all (except Prime95). I use Cool 'n' Quiet so most of the time my CPU is underclocked anyways. But gimme FPS when I need it!

I know I'm not stable, nor is my PC. This debate will go on 'cos some ppl want stable, some (like me) don't really care. I ain't doing anything important on it anyways.
 
know I'm not stable, nor is my PC. This debate will go on 'cos some ppl want stable, some (like me) don't really care. I ain't doing anything important on it anyways.
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Words of wisdom from a brand new member...........
 
Originally posted by: flawlssdistortn
Do you think it's possible for a system that's not prime95 stable to corrupt files that it's downloading or installing?
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I'm not saying that data corruption is a direct result or logical extension of a system that's not Prime95 stable. I'm just suggesting that there's a correlation between system stability and data corruption, and Prime95 is one measure of system stability.
 
haha, prime95 blend stable (ran for 4.5hours before i killed it last nite). 😀

I cranked the fsb up to 175, dropped the multi to 11.5 (2013mhz), and tho i lost about 60mhz i get a small boost in fps in d3, i guess cos the mem bandwidth has pumped up (tho had to relax timings to 2.5, 4, 4, 10 😛 ). vcore at 1.7v

I suspect that i could push the fsb up to 180 (no pci/lock so it all goes pear-shaped after 182), but i cant be bothered screwing around right now
 
Originally posted by: dug777
I can't run prime95 at my oc (2000+ to 2600+), but have no problems whatsoever (literally...none) with my stability with any of the other programs i use, far cry, d3, sims2, simcity4, IE/Excel/Word etc, and can happily encode dvds while running winamp and using IE at the same time, benching with 3dmarks from 01-05 doesnt reveal any instability, as doesn't memtest, superpi, or the sandra burn-in test (ran the cpu tests/mem bandwidth/cache/file system combo 100 times the other day after i discovered i wasn't prime stable with no probs, and have left it running overnight with no probs b4), and my machine runs for 5 days or more between restarts (tho hibernated every nite, too noisy, and fan lights 2 bright for sleeping 🙁 ).
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Pretty-much every single thing that you listed there, is mostly integer-operation-based, not FPU. The only ones that I could see, would be possibly Far Cry, SuperPI (I'm not familiar with that - is it integer or FPU-based?), and possibly Excel, although you'd never know whether or not your results were incorrect.

Originally posted by: dug777
So what other programs will show up the prime instability?
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Basically, FPU issues won't cause crashing or instability - they will simply return the wrong numerical results. If that's acceptable to you (and I would hope not, since you listed running Excel as one of the tasks that you do), then continue with your overclock. Otherwise, if you care about proper operation of your computer, I would step it back down a ways.
 
Originally posted by: dug777
meh...ok

(but like a little kid who wont shut up 🙂 -i would be interested to see my problem recreated under another piece of software, it just interests me since i am clearly completely prime unstable (illegal sumout immediately 😛 ), but the the other apps aren't screwy. As pple have mentioned i have unknowingly been running the risk of hdd corruptions etc etc, but i find it hard 2 believe that i have just been very, very lucky for the past 6 months. (i'm not trying to argumentative here, genuinely interested)

Could it be my psu (i can't even connect a burner or drop in another 512mb stick without random crashes in games)?
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Yes, it could, and if your system power is *that* marginal... wow, that's just scary. You must not care very much about your PC at all, I guess. Take my advice - buy yourself an X-box for gaming, it involves much less administrative overhead and upkeep than a PC.

Edit: I see that you backed off the OC a bit - good. Consider a PSU upgrade, and also consider if you really want to run the risk of IDE data-corruption, because of running non-standard PCI bus speeds, if your chipset doesn't support async PCI or proper divisors at that FSB. You could be risking your data far more than a CPU OC would, in that case.
 
So far, using P95 on a new Athlon XP 2500+ I just assembled & OC'ed is still stable @ 12.5*200 outta my workbench. No testing @ stock speeds. Been running for 2¼ hours @ 1.80V on a A7N8X-D motherboard with Kingston HyperX (2*256MB) in dual channel. Being it passed the first two hours of priming, I am confident it will still hold when I check the 24hr limit. But only time will tell.

I was just asked to build a system based on the XP Barton core to have a good OC yet be stable in 48 hours. So far things are looking good, next up will be the FX5900XT ViVo... I do not think much of a OC will come outta that 😕

If a system does not pass all my testing, I do not sell it as stable and clock things down until they are. I was given a time frame on this computer, so I did not have time to test things @ default. Upon first booting it up, I OC'ed it before doing anything else.
Further tests will include 40 3dMark 2001 loops, 20 2005 loops (Prior was 2003), (Memtest already passed), a powerpoint presentation while a DVD burn and a DivX encode running in the background. Every now and then.

Alas, I still have yet to come up with a better way to test stability. I am open to suggestions, I do not think this computer will pass all tests (mainly the last) due to a lack of memory. BTW, for peats sake, a system is not 100% stable if it fails any test, including p95.

Goi nailed it right on the spot. If it fails, it is because something is not working. Just because it is not important to you, does not mean it is not important. P95 along with many other stability tests are key to system stability. It must pass all to be considered stable. Just because it passes what you like does not mean it is stable by a long shot.
 
Originally posted by: Goi
jayoinoz, if you aren't doing anything important on your PC anyway, what's the hurry? 🙂
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You're probably right. The temptation is just TOO much though... 🙂


Cheers bendixG15 :beer:
 
LOL I was just chatting about this in the general section

In my view there are two kinds of people when it comes to computer stability. Those who decide themselves when their computer is stable or those who use P95 as the "holy grail"

I am kind of in the middle. I mostly go for P95 stable for 8 hours and if it does that I think its fine. But if it does not I may stay at that OC if it passes 3dmark loops and Sisandra loops,

For a machine that I do nothing but surf, write docs, play games, IM, etc then stable for me is

3dmark03 looping for anything over 8 hours without crash
Sisandra burn in for anything over 12 hours without crash

Thats stable for that machine for what I do.

I do not have what I would call a "mission critical" machine, but if I did? I would want P95 to run for 24 hours prolly without issue.
 
Originally posted by: cbehnken
If it's not stable running Prime95, it's not stable. The only reason Prime95 fails is because your computer cannot calculate numbers as accurately as they should be.
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And what is computing all about? Manipulating numbers... So failure in Prime 95 (excluding incompatibilities adn bugs) means your computer is not stable and you will corrupt your data ever so slowly and pay dearly afterwards.
 
Originally posted by: dug777
haha, prime95 blend stable (ran for 4.5hours before i killed it last nite). 😀

I cranked the fsb up to 175, dropped the multi to 11.5 (2013mhz), and tho i lost about 60mhz i get a small boost in fps in d3, i guess cos the mem bandwidth has pumped up (tho had to relax timings to 2.5, 4, 4, 10 😛 ). vcore at 1.7v

I suspect that i could push the fsb up to 180 (no pci/lock so it all goes pear-shaped after 182), but i cant be bothered screwing around right now
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I have seen situations where it takes P95 13 to 24 hrs to detect a fault on small test only. 4 hrs is just a start.
 
And there are incompatibilities to be sure. For instance with the latest ATI drivers I can not run the blend test. it just stays on the 1st test and never finishes and uses hardly any cpu. Others have also reported this problem.

Its not like the makes of P95 update it all the time. When was it last updated. Feb of 04 I think?
 
I'm too impatient to run P95 for too long. I don't do anything important on my system, so it's all fine and dandy for me when overclocking. I'll prime for maybe an hour, and if it works, I go with the flow until I get an issue playing a game/application, in which case I back off my OC a little. It's a long term fine tuning process that requires very little waiting for a program to crunch numbers. Don't be lazy like me 😛
 
Originally posted by: Avalon
I'm too impatient to run P95 for too long. I don't do anything important on my system, so it's all fine and dandy for me when overclocking. I'll prime for maybe an hour, and if it works, I go with the flow until I get an issue playing a game/application, in which case I back off my OC a little. It's a long term fine tuning process that requires very little waiting for a program to crunch numbers. Don't be lazy like me 😛
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Why not just let it run in the background then? Leave the computer running for a night. See what happens. Running Prime95 for only an hour is basically worthless; might as well not even bother. It might even take that long for CPU and case ambient temps to level off at their max values.

 
I hate people who are so paranid about Prime95. Prime95 is an excellent tool that I often use. But I only let it run for 30 minutes and if it passes that, it's stable for anything. I have never ever had a problem doing it that way.
 
my new build is an interesting beast. It has cheapo water, and is totally prime stable for days if I blow a fan at the case. If not, the temps get too high and a thermal failure happens. On the other hand, the idle and normal load temps are fine without the extra fan. I am keeping it at that high overclock, and watching the temps. so far, so good🙂
 
Originally posted by: gururu
I stopped using prime95 a long time ago. games and movies have always let me know when something was amiss. fine tuning an overclock usually takes me a good couple of weeks as I believe it should.
IMO, the reality is that prime95 only tells you that your system is stable enough for prime95 but doesn't guarantee that your system is absolutely stable. as for me, my system only needs to be stable enough for the apps I use.
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Agreed....

Prime is the not the end all anymore in mine and many other ocers minds....

Prime has been unreliable for quite some time.....

I have used it and had it run for 48 hours to have divx and mpeg2 encoders fail, autocadd error out in rendering, etc. I don't trust it.

I use tmpgenc and encode at least a 4-6 hours encoding VBR multipass to test as well, as run superpi 32mb, and many things in multtasking mode to stress the HT. I also still run the memtest. Acually in my current setup prime95 doesnt error in a 12 hour test so in this case it seems to jive, but I have seen where there is more and more glitches in the program as they have made it far more complexed then the older days....

One of more intense is I run FH (1 instance non stop then run a 4-6 hour encoding (now takes a bit longer) and or run a rendering of one of my architectural rendering that can take 2-8 hours depending on resolution, fps, movie type, detail and shading, etc. Autocadd is extremely sensitive as well as tmpgenc and they will eror out at the slightest hint.
 
Originally posted by: Lithan
If you can't pass prime it's not because somethings wrong with prime it's because your computer ISN'T STABLE. It doesn't matter if you can run 3dmark, if you can't pass prime (or anything else that's properly coded), then your machine ISN'T STABLE. You may be happy with a machine that ISN'T STABLE. But you can't call it stable because it ISN'T STABLE. You might as well say that a table missing a leg is perfectly stable because you never bump it or put anything on it, so it doesn't tip over. Always funny seeing people sell cpu's as stable @ XXXXmhz, then someone buys the cpu and it can't even get close to those speeds. The sellers excuse? Well it ran so and so a program just fine. You can't call something stable unless it runs EVERYTHING. And so far Prime is the best program for testing cpu stability. Get the picture?
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I thought Prime was more memory-oriented? I could always run the small FFT test just fine, but when I ran the Blend or Large FFT test it would error out in a minute.

I have a 3200+ with PC3200 Ballistix RAM. The RAM was never stable at any speed whatsoever. I then upped the memory voltage from 2.7 to 2.8 and the system was Prime stable @2.1 Ghz. I'm slowly upping it back up to 2.4.

I was just always under the impression the Prime was used more for memory stable than anything else.
 
I'm a noob that didn't read the whole thread.

On the other side of the coin, if I overclock my CPU, I can run Prime95 for hours and hours (I've done 22+ with no errors) but it will later give me a bsod while idle!
 
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