System crashes when running X

[Reuben D. Budiardja]

Hello,
I have a machine running RHEL 3 that crash / completely lock-up randomly. I 
think I have narrowed it down that this happens when I am running X and using 
the system for normal desktop activity (watching movie, scp-ing files, etc).
The video card is XFX Nvidia GE Force 5200, using the latest nvidia driver. To 
be exact, this is the card that I have:
http://www.newegg.com/app/ViewProductDesc.asp?description=14-150-042&depa=0

The lock-up mostly happens when there's file IO (like SCP) going on. I've 
tested my RAM using memtest86 running all test for two days straight and it 
did not find any error. I've tested my processors using mprime program 
running in 'torture' mode for 3 days straight and they're fine. 

The machine would run fine for weeks or months if in runlevel 3 before, doing 
all kind of things (backup-ing / transferring Gigabytes or hundreds of 
Gigabytes of data, webserving, etc). 

So I am not sure what else to check, or how. Is it more likely a software 
problem, or the video card (hardware) problem? Does anyone have the same card 
running in RHEL 3 or other OS (ie. fedora) and can tell me their experience ? 
Does anyone know a utilities or how to stress test a graphic card ? How do I 
tell if it's more of video card problem or if it's the motherboard ? I really 
hope it's not the motherboard problem, otherwise it'd a real pain.

Any help or suggestions would be greatly appreciated.

Thanks

RDB.
-- 
Reuben D. Budiardja
Dept. Physics and Astronomy
University of Tennesse, Knoxville, TN

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