Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly  
We are NATO-free zone

Re^2: Direct SCF vs conventional SCF

Denis Zavelev

Hello, Alex!

Thanks for the response and for the next post.
As we can see from that pdf, SATA controller speed is important in some case of conventional SCF, so in such cases we'll probably need two (?) PCI-E x4 (or x8, x16) SATA controllers and several SSDs (1 SSD for 2 threads). Using direct SCF lets us not to buy any SSDs and controllers at all but will it lead to better performance?
Using direct SCF usually leads to >95% CPU utilization but it's not a sign of higher performance. Were there any test direct vs conventional SCF?

And a question concerning keywords: does MWORDS=400 means 400MWords for each thread?

>sorry I do not have a definite answer to your question.

>I personally prefer direct SCF and I think most of our users
>use direct SCF for HF and DFT. On the other hand I know some
>users who use RAID arrays built of inexpensive SSDs.

>As to memory, Filrefly is limited by ca. 490 MWords of RAM
>per process i.e. a parallel run can use lots of memory.

[ Previous ] [ Next ] [ Index ]           Mon Jan 14 '13 3:49pm
[ Reply ] [ Edit ] [ Delete ]           This message read 1099 times