AMD Opteron memory bandwidth (was Re: CPUs for a Beowulf)

[Bill Broadley]

On Tue, Sep 09, 2003 at 09:09:46AM +1000, Chris Samuel wrote:
> On Tue, 9 Sep 2003 04:18 am, John Hearns wrote:
> 
> > Seriously though, you might find that 64bit AMDs aren't that expensive.
> 
> My understanding is that memory bandwidth with Opterons scales with the number 
> of CPUs due to the HyperTransport architecture, which could be a big plus to 
> some people.

This is true.

> I'd be interested to hear whether that turns out to be correct or not in 
> practice!

http://www.math.ucdavis.edu/~bill/dual-240-4xpc2700-icc.png
http://www.math.ucdavis.edu/~bill/4x842-icc.png

I suspect if I used the latest kernel tweaks to pin processes to a specific
cpu and allocate only local memory the scaling would be even better.

Oh, to compare to a P4 (or dual athlon):
http://www.math.ucdavis.edu/~bill/dual-p4-2.4-icc.png

-- 
Bill Broadley
Mathematics
UC Davis
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