[Beowulf] Slection from processor choices; Requesting Giudence

[Mark Hahn]

> >> desktop (32 bit PCI) cards. I managed to get 14.6 HPL GFLOPS
> >> and 4.35 GROMACS GFLOPS out of 8 nodes consisting of hardware
> > ...
> >> As a point of reference, a quad opteron 270 (2GHz) reported
> >> 4.31 GROMACS GFLOPS.
> > 
> > that's perplexing to me, since the first cluster has semp/2500's,
> > right?  that's a 1.75 GHz K8 core with 128K L2 and 64b memory
> > interface.  versus the same number of 2.0 GHz, 1M cores each with
> > 4x 128b memory.  I really wouldn't expect them to be that close - 
> > any speculation on why GROMACS runs so poorly on the much better
> > SMP machine?
> 
> <googling for motherboard specs>
> Aha, Socket 462. The Semprons he used are K7 based.

OK, even more so - how does an even older cpu with lower clock,
slower memory and only gigabit interconnect beat a quad-opt.
it seems like some other factors were determining performance.