Prime 95: How many hours should I run it?

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teletran8

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I'm OCing my CPU to 4-4.125GHz. How many hours do you [H] OC'erz recommend I run before "those" settings are considered stable? (On average)

And Once I get that dialed in and average Prime 95 stability going steady. I want to drop my CPU/NB/Hyper Transport Volts to their lowest stable levels and call it a day on my 4.0GHz AMD X3. Thx.
 
depends on what you consider stable... i test a certain configuration for 24-48 hours before i start folding on it, but that is because folding needs the system to be more stable then if you were just web browsing and listening to music or your work units will fail.

you should be able to get more then 6-12 hours without any error for it to be considered decently stable though. any less time isnt really a good indicator of stability.
 
I usually run it until the temps stabilize (takes around an hour) and then after that I will run it for another hour or two to be sure. If its a PC for a client I will run several tests over a 1 day period.
 
I would use linpack over prime, or if you want to be really sure use both (not at the same time!).

Linpack will find instabilities faster while you're tuning your OC.
 
Generally 10-20 passes of LinX or roughly 1hr of Prime95 will give you fair stability; I do that every time I adjust something (ie bclk or multiplier).

Final stability check is 20 passes with all ram in LinX or 8+ hrs of Blend in P95. (minimum)
Usually I let them run longer just because I start them before I go to bed or work and by the time I wake up or come home they're past the 20 run/8 hr mark.

IMHO Linpack is a better stability checker nowadays than Prime95. I've had Prime95 complete with no problems and then the system will crash at some point in LinX if I run that.
 
I have had prime 95 pass 24 hours with out problems but folding will crash the oc I was doing in 4 hours or less. I would suggest using a variety of testers.
 
On the topic:

yesterday i re-enabled HT on my 930 without adjusting voltages, and linx BSOD'd it in 10 seconds while P95 took about 3 minutes (BSOD on the second test). It was a lulzy day, and ended up needing 0.1v more for stability on the same clock speed.

Anybody know the appropriate settinsg for linx? Like should i be concerned with the amount of ram usage or no?
 
12+ hours will get you standard desktop/gaming stable. 24-48hrs for those that want to get really anal about stability (not that it's a bad thing). :)
 
ghost6303 said:
depends on what you consider stable... i test a certain configuration for 24-48 hours before i start folding on it, but that is because folding needs the system to be more stable then if you were just web browsing and listening to music or your work units will fail.

you should be able to get more then 6-12 hours without any error for it to be considered decently stable though. any less time isnt really a good indicator of stability.
Click to expand...

I have it easily 20 minute stable. I don't do medical folding on it at this time, I know what you mean though. I just want my gaming and benchmarking 100 percent stable. I've had crashes on Team Fortress 2 when my prime is stable for only 5-6 minutes, but 20 minutes of Prime 95 has giving me 100 percent stable Team Fortress 2 online gameplay ( And I played like 5 hours last nite with no crashing.) I also leave torrents on at night so I need 24/7 stability, but at Nights my CPU uses Cool N Quiet and runs on less voltage with that technology enabled, so it's far from stressful) I also run Magic Jack phone system to receive phone calls instead of paying 40 a month for a phone service I pay 40 a year and 22 every consecutive year for the subscription/service. That is as long as the USB device does not break, then it's 40 a year cause I have to buy a new USB jack. If you don't acidentally break it then I just egt the 20 dollar subscription with tax so it's around 22.

Gaming right now is the most stressful activity I use my PC for, and TF2 is far from a demanding graphics engine. I should probably pick up Crysis Warhead or Metro 2033 to also test my system stability, what do you guys think? Thx.
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OK I'm about 1 hour stable with my current settings, I don't like the fact that my CPU reached 72 degrees when it's rated TJ Max is 70 Degrees, maybe I can drop my CPU Volts by an increment or 2 and check for another Hour stability today or tommorrow and hope TJ max isn't reached that time. Maybe 1 Hour Prime 95 stable is good enough for gaming?

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Dang, I didn't realize just how much voltage was necessary to OC those AMD chips.

I think everyone just about has different take on what is considered "stress test stable". I personally don't think one particular way is better over another, but I do think what you ultimate will use your rig for should determine just how far you're willing to go with stress testing.

I don't do any serious if-I-lose-my-data-I'm-screwed level of work other than taxes on my system so I could care less about stress testing for 24 hours straight with any program.

I usually run prime95 after I OC. Blend test in particular is best for checking for overall system stability. I will run this for anywhere from half an hour to couple of hours, but usually no more than 3. If all's well, I will fire up some benchmarking programs like Vantage, Heaven, 3DMark11, etc to see if they will run all the way through. If so, I will fire up couple of system demanding games like Crysis Warhead, Crysis 2, Metro2033, etc for couple hours at a time. The game testing process may take couple of days or so to complete since I will not sit there and play all of these games in one sitting. I have found that this method for me works best because it allows me to interact with my system while I put it through its paces to see if it's stable. If the games crash, I will tweak my settings a bit like adding a few voltages here or lowering my OC until I can run through the games without issue.

The method I use is simple but I find it effective for my use and has not failed me so far. Some may find it "not enough" but I haven't seen the need to take it to extreme levels, i.e. 24 hours or more of continous stress testing.

IMO, it should really boil down to what your comfort level is in regards to how you feel about what "fully stable" means to you.
 
I would say to run it for at least 24hrs.

Prime95 will be the most strenuous application most users will ever use. Even if Prime does fail, there is a good chance that your CPU is 100% stable in everything else that you would throw at it any given day. Games, applications, etc.

My current PC fails prime in 5mins-1hr depending on its mood. But it has yet to blink at any non benchmark/stress test game or application.

If you can solve issues relating to prime95 by simply raising the voltage without getting into too much of a heat issue, then by all means do it. If you cant stabilize the pc in prime, yet it runs everything else just fine, that's your call.
 
we really need a definition of what is considered "stable" and what the word "stable" specifically means. no computer is 100% stable in regards to bit errors; all computers get an incorrect bit or corrupt instruction here and there. 99.999% of them you would never notice and are automatically handled by error-correction at the kernel level.

there is also a large difference between a random byte of data that gets computed and returned incorrectly (in any of the dozens of data handling/processing components of a computer), an error that would result in a program crashing, and even worse yet- an error that causes a blue screen.

we need to also realize the difference between types of use. web surfing is not very demanding. it requires extremely minimal CPU time, a small (100-500MB) amount of RAM, and light disk (mixed read/write) and video card usage.

gaming requires a decent amount of CPU time (though its not pegged at 100%, and it normally uses only a few instruction sets), very heavy graphics processing, moderate (500-2000MB) RAM usage, and mostly disk reads.

folding or video rendering, or any other type of pure number crunching, usually uses a specific instruction set or type of calculation, with 100% CPU usage. the video card is either used completely, or almost not at all (no middle ground usually). RAM usage is a wide range depending on the specific task. disk usage is usually moderate to heavy, with a decent amount of writing.


so you can see what you might call "stable" for one application could easily be unstable for another. if the instability for your specific CPU ( at your specific settings) doesnt make itself known while reading yoru email, that doesnt mean it wont cause problems trying to encode a video. so to quantify the amount of stability with words like "moderately" or "fairly" is only accurate when you know how the system you are describing is used.
 
My standard for stability is much lower than many. I run linX for 20 passes using all ram and call it a day. Maybe it would error on pass 21 or Prime would fail at 4hours, but I don't care. In 2.5 years of having my i7 920 between 4 and 4.3ghz, I still have yet to see a blue screen no matter what I am doing.
 
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