Discussion Forum

Hi

I would say a lot of RAM (I have 48Gb and my WS is 8 months old) then several cores (I have 2xCPU of 6x2 cores but I mostly run with12 of the total 24 as the others are mutithreaded and the difference in spead is not that big. Then you need a high speed link betwenn your RAM and your CPU(s), hence a rather new board (I have an Intel 5520SC). Finally you need a or two high speed disks with a good link to the CPU bus and finally a good graphics card. Not to forget a power supply adapted (mine is 1kW with a helicopter fan, noisy but heats nicely up the office in the winter, not that fun sommer times ;)

But this is still probably a small WS compared to what other are using, or to a cluster set-up

Any how the best way to get your model to solve quickly is to reduce it's complexity by some pre-analysis of the type, use symmetry, use 2D instead of 3D, replace a full physics analysis with a constant gradient when you know the analytical solution and finally give good guesses for the initil conditions, the default "0" is nice and mostly converges, but it takes time, and you might end along the wrong track

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Have fun Comsoling
Ivar

Hi,

well I'm using COMSOL very often on a "normal" Desktop PC with an i7 CPU and 12GB RAM. I solve transient 3D Heat Transfer problems with temperature-depending properties. Those models fit easily to this computer (iterative solvers) and it runs quite fast. But at the moment when you need NS, the complexity increases steeply and you getting memory issues.

Sometimes I really don't think, that you need a real WS. Of course, their stabilty is higher and they are more optimised than normal PCs, but I don't know if this makes a big difference. The ECC-RAM for WS is very expensive - this can make a difference :) And of course - buying a desktop-PC which has 48GB RAM (or more) isn't easy, too :)

I'm really waiting for the moment, when you can use e.g. amazon EC2 whith Comsol :) Then you can easily switch to high performance on demand if you realize that you need it. It even gives you the possibility to determine what you need.
Recently I read, that there is a beta Version of CAELinux (free and open source Linux distribution with serveral tools for CAD, FEM, FVM, ...) for cloud computing an EC2. That could be a clear advantage for these tools - hoping COMSOL will follow :)

best regards

Thank you very much Ivar for your comments. I really appreciate it.

I should be getting COMSOL any time soon.

Luis

Dear Kai,

Thank you very much for all your information.

Best regards,

Luis

Hi to all,

I just have one question?

does ECC memory makes a difference? I know it does in our budget, but does it makes it in the results or the computation time?

cheers,
Felipe.