Oh and wrah- the question is how much of an affect does the lower speed KM266 memory controller actually cause? There are Nforce2 boards that at twice the price offer a far superior memory controller- but this has to result in a 25% increase in folding power to outweigh the cost!
Well, there are also cheap SIS chipset based mobos with everything onboard. Not sure if they would be faster though.
And there is the nForce based Asus A7N266-VM that Neil mentions.
On the Duron/AthlonXP matter, a few usefull quotes from the f@h forum:
(somebody tested out which is faster by underclocking his Athlon)
18minutes/frame on the t-bird system running at 7.5x124=930mhz vs. 44minutes/frame on the duron system running at 8x133=1066mhz.
Quite a difference. Though he used an older Duron (spitfire core) that didn't have SSE. Durons > 1 Ghz do have SSE.
p537_BBA5_N_in water folds 6.5x faster on a T'Bred 2.4GHz@192FSB DDR SDRAM than on Spitfire 910MHz@140FSB SDRAM.
That means that T'Bred crunches this particular gromac WU 2.5x faster than Duron (MHz per MHz)
My conclusion: Gromacs eather like great mem. throughoutput (2.6GB/sec T'bred - 1.1GB/sec Duron platform) and/or more on-die cache (384kB T'Bred - 192kB Duron).
But it could also be caused by the much lower bandwidth of the Duron. The fahcore does run faster with a higher bandwith:
Downclocked my T'Bred to 1.25GHz.... folding a Gromac unit using optimizations
12.5x100MHz - 1.25GHz(Mem bandwith - 1.4GB/sec) - time per frame 5:41sec
7.5x166MHz - 1.25GHz (Mem bandwith - 2.4GB/sec) - time per frame 5:17sec
My Duron machine has about 1Gb/sec mem. bandwith, and onboard VGA uses maybe 20-30Mb/sec (2-3%).
So, the only logical explanation is that Gromacs LOVE more on-die cache, or the SSE unit found on T'Bred crunches WUs a lot faster than 3DNow! unit on Duron.
Which also answers your question about fsb, Zhentar.
So fsb/memory bandwidth does matter a bit, but only boosts the speed about 7%.
The bandwidth is an issue with Gromacs but only makes about a 5-10% difference that I have tested from 133-200-266 fsb.
Cache also makes about a 10% difference between 128-256 on the Durons/Athlons.
15-20% difference, but at equal Mhz's. So this answers my question, 6 Durons are about as fast as 5 Athlons. I would go for Athlons then.
Run SuSE 8.2
Right now I'm going for Redhat 8.0, since they used that in that how-to article about building a farm. The question has been asked a few times on the f@h forum which linux would be better, and there was allways a different answer, which never sounded very objective
. Would SuSe be better then Redhat and if so, why?
Time for breakfast now.