[gmx-developers] GROMACS performance on Opteron Dual Core processors!

[Erik Lindahl]

Hi,

On Sep 25, 2006, at 6:33 PM, Florian Haberl wrote:
>
> The market for cpus is always in fast movement, today Woodcrest  
> (posted on the
> mailing list some weeks ago) is faster, but noone can say if the  
> new opterons
> (better socket, perhaps quad cores) is faster, or if even Cell or  
> Clearspeed
> will be the next big number.

The main reason for the amazing woodcrest/conroe/merom performance is  
that Intel now has 128 bit SSE bandwidth, i.e., it can complete most  
SSE instructions in a single clock cycle instead of two. Since all  
Gromacs innerloops are available in handcoded SSE assembly this makes  
a major impact.

Rumor says it AMD will move to a 128 bit SSE engine too, but not  
until late 2007 or 2008. The first quad-core Opterons will still be  
the old micro-architecture. Opteron still rules when it comes to  
general memory bandwidth, though. If we're lucky, this means new  
price wars ;-)

Cheers,

Erik