What hardware are you using? Tips for new user?

greenleader · March 15, 2013, 09:55

There is not not much discussion about hardware on the OpenFOAM forum

I am currently playing with OF in a virtual machine under XP on an oldish Intel Core-duo E6300, but I plan to move to new hardware soon.

I don't know a lot about computer hardware - my questions are:
- should I go for a single or dual processor system? (can I run on one processor and then add another later if I wanted more power?)
- what processors are recommended?
- are there any brands/processors etc that one should avoid for compatibility reasons?
- whats important when buying RAM (apart from the size)? I think I'd start with 16GB but select a system that I could expand to say 32GB if I wanted to later.

I am starting out with 2D problems with less than 100,000 cells but when I build up to 3D geometry I expect 5M cells is likely.

regards
Steve

elvis · March 15, 2013, 14:12

Hi,
the Hardware forum at cfd-online is not bad and there are also people discussing
on hardware that is suitable for OF, but the discussion for other software can be read as well
because the ratio 'cells/CPU" is important. I think you do not see a acceleration below 200000 cells/CPU.
Intel CPU's have better performance than AMD in this area. Some people & companies have worked on GPU acceleration for OF. You find announcements in this forum and presentations @ OF-workshop

greenleader · March 16, 2013, 09:42

thanks for pointing that out - I was focused on the openFoam forum and I had not looked in the more general forum. I have now found some useful tips...

kwardle · March 19, 2013, 12:04

I would disagree somewhat with what Elvis has said regarding cells/CPU. While it is very dependent on the physics you are looking at, for interFoam based VOF solvers I have found you can get good speedup at much higher per processor distributions (~25K cells/proc). Maybe you had an extra "0"? That has been my experience anyway. And if you are very impatient and not computational resource limited, I sometimes run even lower (7500K cells/core), but this is very aggressive and about the limit where you don't get much more speed-up and start to drop below 75% parallel efficiency. This is for multiphaseEulerFoam anyway. Just my 2 cents.

immortality · August 1, 2013, 08:21

hi
What do you mean by acceleration originated by "cells/CPU"?could anyone clarify more in this relation?

March 15, 2013, 09:55	What hardware are you using? Tips for new user?	#1
greenleader New Member Steve Join Date: Sep 2012 Location: Perth, Australia Posts: 17 Rep Power: 13	There is not not much discussion about hardware on the OpenFOAM forum I am currently playing with OF in a virtual machine under XP on an oldish Intel Core-duo E6300, but I plan to move to new hardware soon. I don't know a lot about computer hardware - my questions are: - should I go for a single or dual processor system? (can I run on one processor and then add another later if I wanted more power?) - what processors are recommended? - are there any brands/processors etc that one should avoid for compatibility reasons? - whats important when buying RAM (apart from the size)? I think I'd start with 16GB but select a system that I could expand to say 32GB if I wanted to later. I am starting out with 2D problems with less than 100,000 cells but when I build up to 3D geometry I expect 5M cells is likely. regards Steve

August 1, 2013, 08:21		#5
immortality Senior Member Ehsan Join Date: Oct 2012 Location: Iran Posts: 2,208 Rep Power: 26	hi What do you mean by acceleration originated by "cells/CPU"?could anyone clarify more in this relation? __________________ Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked.

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March 15, 2013, 14:12		#2
elvis Senior Member Elvis Join Date: Mar 2009 Location: Sindelfingen, Germany Posts: 620 Blog Entries: 6 Rep Power: 24	Hi, the Hardware forum at cfd-online is not bad and there are also people discussing on hardware that is suitable for OF, but the discussion for other software can be read as well because the ratio 'cells/CPU" is important. I think you do not see a acceleration below 200000 cells/CPU. Intel CPU's have better performance than AMD in this area. Some people & companies have worked on GPU acceleration for OF. You find announcements in this forum and presentations @ OF-workshop

March 16, 2013, 09:42		#3
greenleader New Member Steve Join Date: Sep 2012 Location: Perth, Australia Posts: 17 Rep Power: 13	thanks for pointing that out - I was focused on the openFoam forum and I had not looked in the more general forum. I have now found some useful tips...

March 19, 2013, 12:04		#4
kwardle Senior Member Kent Wardle Join Date: Mar 2009 Location: Illinois, USA Posts: 219 Rep Power: 21	I would disagree somewhat with what Elvis has said regarding cells/CPU. While it is very dependent on the physics you are looking at, for interFoam based VOF solvers I have found you can get good speedup at much higher per processor distributions (~25K cells/proc). Maybe you had an extra "0"? That has been my experience anyway. And if you are very impatient and not computational resource limited, I sometimes run even lower (7500K cells/core), but this is very aggressive and about the limit where you don't get much more speed-up and start to drop below 75% parallel efficiency. This is for multiphaseEulerFoam anyway. Just my 2 cents.