[Q] slow execution at fedora 13

[Byoung_Jeon]

Greeting,

I am testing a molecular dynamics code for performance check on two machines

1. Intel Xeon CPU E5410 @ 2.33GHz
OS: Red Hat Enterprise Linux Server release 5.1 (Tikanga)


2.ntel Xeon CPU W3680 @ 3.33GHz
OS: Fedora release 13 (Goddard)

Same intel fortran 11.1, and I am using optimziation option as "-xHOST -O3 -ipo -no-prec-div ". Tested code is for
serial run and tested with a single core only.

Test results are:

1. 15 sec
2. 17 sec

Even though W3680 shows more than three times of performace than E5410 (http://www.cpubenchmark.net/cpu_lookup.php?cpu=Intel+Xeon+W3680+%40+3.33GHz), the execution speed is slower (!?).

I used same compiler/option and I have been trying to figure out how to accelerate but in vain.
To my best knowledge, Fedora 13 is not supported by ifort yet. If I reinstall any supported OS like ubuntu 9 then
will I get higher speed-up? Or any other comment will be very appreciated.

Best regards,

Byoungseon

PS. PC of model 2 is dell T3550. I enabled hyperthread from the CMOS (it was disabled from the beginning).

[TimP]

If you are running only 1 thread, you don't want to enable HT.
It seems unlikely that an older linux version would run faster on such a new CPU. Did you try using taskset to pin to a single core (one not used by any other job)?
Do you have as much RAM on the newer CPU as on the older one, in case your application requires much memory?