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-   -   IcoFoam erformace on 32 bit vs 64 bit (http://www.cfd-online.com/Forums/openfoam-solving/60510-icofoam-erformace-32-bit-vs-64-bit.html)

henry August 25, 2005 10:57

We have found that for most bu
 
We have found that for most but not all cases running 64bit on the Opteron is faster than running 32bit but the difference is rarely greater than 15%. I doubt you will see much improvement by changing the optimisation flags but we haven't tested all the options.

maka August 25, 2005 11:09

A friend suggested that usuall
 
A friend suggested that usually -tp k8-64 may give good improvement but I have to admit that yet I can not find the file where, I should use this option. I'm looking in $HOME/OpenFOAM/OpenFOAM-1.1/wmake.

Can you give me some hint of where is the file that controls the compilation options.

Many thanks,
Maka

henry August 25, 2005 11:14

The compilation options for ea
 
The compilation options for each platform are in OpenFOAM-1.?/wmake/rules. For version 1.1 you will want to put your optimisation options in the file linuxAMD64/c++Opt and for version 1.2 in linuxAMD64Gcc4/c++Opt if you are using gcc-4.0.1 supplied with the release.


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