PC GAMESS-related discussion club

Alex Granovsky
gran@classic.chem.msu.su

the questions you are raising are the difficult ones. I would be glad if every users of this forum will join this discussion. I can provide you only by several hints which could make the decision simpler.

1. Definitely, the OS should be the 64-bit one. This is because PC GAMESS uses 64-bit computation kernels for better performance running under 64-bit OS. This is clearly impossible under 32-bit OS.

2. PC GAMESS runs equally fast under Linux and Windows.

>I heard the parallel I/O under Windows is not very efficient...

3. The problem is that it is not better under Linux, and is even worse in most cases.

4. Running under Linux, PC GAMESS will be able to allocate more memory.

5. Are you planning to use these systems exclusively for PC GAMESS or not? If you aren't you should consider the availability of other software for the selected OS.


>2. CPU
>I am considering a single PC with either a Xeon Quad core E5335 or two Xeon Dual core 5130. The E5335 is more or less equivalent to two 5130 put together so I wonder which solution would be the best for PC Gamess: 1CPU with 4 cores (ie. E5335) or 2 CPUs with 2 cores each (5130).

I would opt for two dual-core CPUs. The reason is that the aggregate memory bandwidth is higher in the latter case due to DIB feature of chipset. Thus, the scalability would be somewhat better. Do not forget to buy four HDDs and organize them as four independent disks, not the raid array - you will then be able to assign a separate HDD as a scratch to each instance of the parallel PC GAMESS process.


Best regards,
Alex Granovsky


On Sun Sep 9 '07, Rudy wrote
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>Dear all,

>As a new user of this forum, I would like to thank Dr A. Granovsky and his team for developing and maintaining PC Gamess.

>I have some basic questions regarding the OS and CPU I should use with PC Gamess:

>1. OS
>Of these four OS, which one would be "the best": Windows Vista 64, Windows XP (32 or 64), Red Hat Enterprise WS V4 (64) and Red Hat Enterprise 5 Desktop (64). I am also considering Fedora 7.
>I heard the parallel I/O under Windows is not very efficient...

>2. CPU
>I am considering a single PC with either a Xeon Quad core E5335 or two Xeon Dual core 5130. The E5335 is more or less equivalent to two 5130 put together so I wonder which solution would be the best for PC Gamess: 1CPU with 4 cores (ie. E5335) or 2 CPUs with 2 cores each (5130).

>Thanks a lot for your help,
>Rudy.