PC specification for OpenFOAM
Hi. I am planning to buy a new PC to run complex CFD simulations using OpenFOAM. What shall I be looking for when buying such machines? I would be grateful for any recommendations!!
Thank you in advance. |
Quote:
Regards Bastian |
Hi Bastian.
Thank you for the quick reply. I will be looking into external subsonic/transonic compressible flows. My grid might reach 5 million cells. What would you think might be the cheapest option? Once again thank you for your time and response, Regards A.D.E |
Hello,
As always, it depend of how money you will spend on ... Anyway, with a small amount of money, the best is to buy 2 to 5 cheap PC with core i5/i7 @ 3.3Ghz with 4 Go ram and Ethernet (~500€ each) connection throug a GigaByte switch. Speedup are far better with multi node than multi core. NB: i've got a far better speed up with 2 core i5 node, with a 2x2core : 4 process, than on a signle i5 with 4 process. With 4+4, speedup are not so good. NB2: with ethernet, do not use more than ~ 5 node, unless you add QDR infiniband card. Olivier |
Hi Olivier,
Thank you for your reply. My budget will be between 2500-3000 pounds Uk I hope. So you think that it might be better to buy more than one machine and connect them together? I can not buy one PC and add cores on it?? My knowledge on setting up PCs is limited therefore I would like something good and simple.. Do you have anything like that in mind? Once again thank you for your consideration and time, Sincerely, A.D.E |
Hello,
I think the main limitation come from Cache memory. 1) If you go with one multicore station, like dual xeon (i.e "professional workstation"), you may get à 2*6 core with one machine @ ~ 3000€, so 2x6 = 12 core, with 2*12 = 24 Mo Cache, and ~ 2.6 Ghz/core. 2) If go with 4 pc, core i7, you get 4x4 =16 core and 4x 8Mo = 32 Mo Cache, 3.4Ghz/core, at less than 3000€, and with real speed up. NB: at work, with the same test case, a single core i5 run on 4 core @ 3.3 Ghz are 2.5x faster than a dual xeon, which run on 8 core @ 2.2 Ghz, and with 2 station with core i5, it's 4x faster, so yes, frequency matter too.) NB2: don't forget to set on one machine a large amount of memory (8/12 Go at least) + graphic card when you will mesh/decompose/ and use paraview ... NB3: for all other station, 2-4 Go is ok if used only as a compute node (1Mio cell ~ 1 - 1.5 Go ram), and no need of hard drive/screen/... olivier |
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