[Wien] How is the performance dependent on CPU cache size

Peter Blaha pblaha at theochem.tuwien.ac.at
Wed Oct 17 08:48:09 CEST 2007

Without explicit benchmarks it is hard to tell, but I'd expect that
cache size is NOT very important (WIEN2k is heavily "blocked" and blas-based,
without this we would run out of cache anyway.
When using mkl it should take care of the actual cache size.

However, as far as I know these processor series differs in:

clock-speed  (cpu-speed) and frontside-bus speed.
Naturally the clockspeed is very important, but I'Äd expect that also frontsidebus
(and related the memory quality (speed)) can be quite important.

Usually, the price of the cpu is only some fraction of the PC cost,
at least if you are not going for the TOT-TOP cpu-model.
So I'd go for a "good" processor (but maybe not for the "extreme-CPU",
because this might be a bit "overpriced".

Johan Eriksson schrieb:
> Dear Wien community
> What difference will 1MB or 2MB or 4MB of CPU cache give in Wien? I'm 
> now thinking about similarly clocked Intel core 2 duo CPUs. Is it 
> justified to pay 4X for a 4MB CPU (E6XXX series) when the cost of a 1MB 
> (E2XXX series) is X?
> Cheers
> /Johan
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> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/

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