[gmx-users] Question about Athlon 64 4800+ x2 (poor performance)

[gromacs3]

Dear users

I compiled Gromacs-3.3.1 from the src-rpm, on my system x86_64 FC5 
(Athlon 64 4800+ x2, 4Gb DDR). When I tested gromacs over one of my 
molecular system I noticed its very poor performance.

Can anybody tell me:

1) What are the defaults setting used by rpmbuild to compile gromacs in 
my system?

2) In case, how can I change this defaults to increase perfomance?

3) Can anyone give me some advice or suggestion on how I should compile 
gromacs in this environment?

Thank you in advance

Sergio Garay
Biochemist
Facultad de Bioquímica y Cs. Biológicas
Universidad Nacional del Litoral
Santa Fe (3000) - Argentina