I suspect something weird is going on. Try booting from the memtest utility. It's available from the RHEL repositories and pay particular attention to the "memory bandwidth" report.
If I had to guess, I'd say you've got e.g. 5300-speed RAM in both machines, but when the machine is filled with RAM the memory controller slows down the bus clock (presumably for power/heat reasons), actually slowing down the RAM. In these circumstances you'll get faster results with less RAM.
Compare the RAM speeds, it's almost certainly your CPU->RAM bandwidth.
Oh, I wouldn't pay much heed to the RHEL vs. SuSE debate on HPC use, I use RHEL-based OSes for HPC all the time.
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||