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Glenn Price September 19, 2001 10:49

Computer lockups
Has anyone experienced computer lockups when running FLUENT 5.5 on dual PIII based machines. We've got several dual 1 GHz PIII machines that can be run as a cluster. Unfortunately, our machines frequently lock-up when running FLUENT or GAMBIT.

FLUENT technical support hasn't been much help other than to say other clients haven't had problems on dual machines. Does anyone run on a dual PIII or P4 machine? What brand name, e.g. Dell?



Scott Whitney September 19, 2001 13:51

Re: Computer lockups
I've got a dual P2, regular P3, and dual P4 Xeon. None of these has recently locked up. Two years ago when using Gambit version 1.0 I did have a lockup about every 30 minutes. However upgrading to Gambit 1.1 corrected the problem.

When a computer locks up, there are four typical reasons: 1) CPU overheats, this should be a problem only when you have overclocked your CPU (running faster than they are rated) or when your CPU fan is failing. 2) Power supply is insufficient for your use. If you added lots of extra items to the machine, this may occur. What wattage is your power supply rated at? 3) Driver conflicts. Make sure you are running as few other programs as possible. For those you do use, make sure the have up-to-date drivers. 4) Program errors. This is what occured with Gambit 1.0. Since most of us haven't had this complaint, I'd say this is not as likely as the other reasons.

I think the best advice you might find is at forums such as,, or

Jonas Larsson September 19, 2001 14:30

Re: Computer lockups
We've run Fluent 5.5 on dual CPU PIII's (Dell Precision 620) and Fluent 5.7 on a dual CPU P4-Xeon (Dell Precision 530). Both of these were running RedHat Linux (7.0 on the 620 and 7.1 on the 530). So far we have not had any lock-up problems. We've had the 620 running for half a year without a single lockup. The 530 is brand new but it seems stable. The only trouble we've had is to get the graphics on the 530 to be stable in Fluent - but I hope that the latest linux drivers from nvidia that we installed yesterday will fixe that (we have Quadro-II cards). .

Scott Whitney September 19, 2001 16:12

Re: Computer lockups
Thanks for removing my redundant post Jonas.

Glenn Price September 19, 2001 16:13

Re: Computer lockups
Thanks for the feedback Scott. Are you running Windows NT/2000 or Linux?

I will check into 1), 2) and 3). I agree, program errors aren't the cause. Things will run fine for quite some time and then it freezes.

Glenn Price September 19, 2001 16:16

Re: Computer lockups
Thanks Jonas,

I'd like to try Linux but our IT group is hestitant and won't support it. I'll look into Scott's suggestions. If this doesn't help, I try Linux - personally, I've run FLUENT on Unix workstations for years without any lock-up problems.

Scott Whitney September 19, 2001 16:37

Re: Computer lockups
I'm using both WinNT and Win2k. I see no stability difference between the two.

John C. Chien September 19, 2001 18:39

Re: Computer lockups
(1). If your machine is on the network, then you should talk to your network people. I had a lot of bad experience with network. (2). If you are running stand alone, try to install as little application programs as possible first. (3).My new PC/PIII has a lot of programs installed, and it hangs up more frequently now (Windows98) in shut down and start up. My old one with AMD was very stable (Windows98). (I am not running Fluent, so these are not Fluent specific.)

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