[Wien] What type of CPU's for big calculations?

[Peter Blaha]

> Do you suggest that a cluster build from Core 2 Duo (E6700) machines is better than a Xeon Dual core (5160, 5080, 7xxx) Cluster.
> In the first you combine 2 CPU systems in the second you may combine at rather the same price 4 CPUs per machine (or more if you like to go 
> for an expensive solution.) 

Some of the Xeons (I'm not sure which one of your numbers) have the same 
architecture as Core2 Duo and are also fine.
Its just a matter of prices and the size of the cluster (or the amount 
of money you have). You might get an E6x00 PC for 1000-1500 Euro 
(depending on the clock speed and memory) and I expect that Xeon servers 
cost much more than just a factor of two. In addition we have seen that 
Xeons still slow down somewhat when all cpus are used.


Of course, it depends a lot on your demands. If you really want to solve 
problems which require matrix sizes above 10000 and if you already have 
enough "basic PCs" for 80% of your calculations and still have some 
spare money, buy a Xeon cluster with infiniband for MPI runs for such 
real big cases.


> The Ithanum are real 64 bit processors, is there any fortran compiler breaking
> the 2GB barrier on the pseudo-64 bit CPUS (Intel or AMD).

The Itanium was always a very nice processor. However, I don't know if 
the dual core Itaniums are already available ?
In any case, I expect that Itanium systems will be at least twice as 
expensive (and they are certainly not so much faster). A year ago we got 
for the same money a Xeon cluster with 72 dual-cpu nodes (single core), 
but the Itanium offer was just 64 cpus !!!

REgards