-----Original Message-----
From: Tony Karavidas [mailto:tony@;encoreelectronics.com]
Sent: Friday, October 18, 2002 1:15 PM
To: 'Protel EDA Forum'
Subject: Re: [PEDA] [OT] memory testing and benchmarking - programs

I looked at the link you provided about prime95, and if you read the
"how it works" section here http://www.mersenne.org/works.htm it says:

"The program runs at the lowest possible priority. You should not see
any impact on your system's performance. The program will use about 8MB
of memory and about 10MB of disk space."

That doesn't seems like much torture to me. :)


Use of disk space has nothing to do with memory bandwidth or processor stress
testing. The program's original function is to search for Mersenne primes.
Its part of a distributed computing project just like Bovine, Seti, Genome,
Intel's Cure, etc.  Therefore since the client is supposed to run at the same
time you are using your computer it is set to the lowest CPU priority so that
it does not lag the system while you are using it.  When your machine goes
idle then the program will use all of the available system resources.  The
"torture test" mode is what is to be used for testing.

Below are comments from the release notes as to the usefulness of the program
for stress testing:

                        STRESS TESTING YOUR COMPUTER


Today's computers are not perfect.  Even brand new systems from major
manufacturers can have hidden flaws.  If any of several key components such
as CPU, memory, cooling, etc. are not up to spec, it can lead to incorrect
calculations and/or unexplained system crashes.

Overclocking is the practice of trying to increase the speed of the CPU and
memory in an effort to make a machine faster at little cost.  Typically,
overclocking involves pushing their machine to the limits and then backing
off just a little bit.

For these reasons, both non-overclockers and overclockers need programs
that test the stability of their computers.  This is done by running
programs that put a heavy load on the computer.  Though not originally
designed for this purpose, this program is one of a few programs that
are excellent at stress testing a computer.


This program is a good stress test for the CPU, memory, caches, CPU
cooling, and case cooling.  The torture test runs continuously, comparing
your computer's results to results that are known to be correct.  Any
mismatch and you've got a problem!  Note that the torture test sometimes
reads from and writes to disk but cannot be considered a stress test for
hard drives.

You'll need other programs to stress video cards, PCI bus, disk access,
networking and other important components.  In addition, this is only one
of several good programs that are freely available.  Some people report
better finding problems only when running two or more stress test programs
concurrently.  You may need to raise prime95's priority when running two
stress test programs so that each gets about 50% of the CPU time.

Forums are a great place to learn about available stability test programs
and to get advice on what to do when a problem is found.

The currently popular stability test programs are (sorry, I don't have
web addresses for these):
        Prime95 (this program's torture test)
        CPU Stability test
        Sisoft sandra

Several useful websites for help (look for overclocking community or forum):
        Also try the alt.comp.hardware.overclocking Usenet newsgroup.

Utility programs you may find useful (I'm sure there are others - look
        Motherboard monitor from http://mbm.livewiredev.com
        Memtest86 from http://www.memtest86.com
        TaskInfo2000 from http://www.iarsn.com/


The exact cause of a hardware problem can be very hard to find.

If you are not overclocking, the most likely cause is an overheating CPU
or memory SIMMs that are not quite up to spec.  Another possibility is
you might need a better power supply.  Try running MotherBoard monitor
and browse the forums above to see if your CPU is running too hot.
If so, make sure the heat sink is properly attached, fans are operational,
and air flow inside the case is good.  For isolating memory problems, try
swapping memory SIMMs with a co-worker's or friend's machine.  If the errors
go away, then you can be fairly confidant that memory was the cause of
the trouble.

If you are overclocking then try increasing the core voltage, reduce the
CPU speed, reduce the front side bus speed, or change the memory timings
(CAS latency).  Also try asking for help in one of the forums above - they
may have other ideas to try.


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.


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)  How long should I run the torture test?

        A)  I recommend running it for 24 hours.  The program has been
        known to fail only after several hours of operation.  In most
        cases though, it will fail within a few minutes on a flaky machine.

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?


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
        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
        then the machines will continue to be stable.


> -----Original Message-----
> From: Matt Daggett [mailto:mdaggett@;mcnc.org] 
> Sent: Friday, October 18, 2002 6:10 AM
> To: Protel EDA Forum
> Subject: Re: [PEDA] [OT] memory testing and benchmarking - programs
> Tony,
> Check out SiSoft's Sandra for a full suite of system 
> benchmarks.  Also if you feel that you might have some faulty 
> memory I'd suggest running a program called "Prime95" for a 
> few days.  The program is very memory as well as CPU 
> intensive because it tried to factor large numbers to find 
> mersenne primes. If your system can withstand the "torture 
> test" feature then you know you have a stable system as far 
> as memory timing, CPU cooling, etc.  The torture test works 
> by factoring numbers of known primes and if the answers 
> computed doesn't correspond with the known solution then you 
> know you have a memory issue.  Its been used widely in the 
> overclocking community (which I used to be a part of for a few years).
> Sandra - http://www.sisoftware.demon.co.uk/sandra/
> Prime95 - http://www.mersenne.org/freesoft.htm
> Hope that helps.  If you are really into memory performance 
> you should get out your BIOS manual (assuming you have a good 
> BIOS) and learn about some of the advanced memory features.  
> On my workstation at home I have some PC100 running at 133Mhz 
> (Crucial RAM is top notch on the fab) and just by modifying 
> the CAS Latency, Bank interleaving, etc I was able to boost 
> my memory performance just under that of DDR266.  Not bad for 
> a no cost upgrade.  Oh yea... and my system will run Prime95 
> till the cows come home... this is where it pays to get high 
> quality RAM and not the cheap stuff.
> http://www.crucial.com <-- arguably the best RAM on the market
> matt

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* To post a message: mailto:proteledaforum@;techservinc.com
* To leave this list visit:
* http://www.techservinc.com/protelusers/leave.html
* Contact the list manager:
* mailto:ForumAdministrator@;TechServInc.com
* Forum Guidelines Rules:
* http://www.techservinc.com/protelusers/forumrules.html
* Browse or Search previous postings:
* http://www.mail-archive.com/proteledaforum@;techservinc.com
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Reply via email to