Hi everybody, I have about 10,000 euro to buy some machine to calculations and I am considering to options: cluster or workststion. Let assume that workstsion has two CPUs and cluster is two units with the same single CPU and rest of equipment is also the same. Generally I need this to calculating not to big cases (say 2,000,000 nodes) so the main purpose is to gain the shortest time of calculations. I got to know that, more or less, comparable performance from cluster (on PC components) I can obtain for half of this price. Does anybody have some experience in this matter? Regards

Hi,

Some important points:

AMD CPUs give local parallel efficiencies about 80% and usually above 90%.

Current Intel CPUs give equivalent local parallel efficiencies around the 80-90% mark providing you only use one core on a chip (that means one core on a dual core, two cores on a quad core). If you use both cores on an intel chip your parallel efficiency drops significantly, 50-60% is common.

The serial speed of high-end Intel chips is better than the best AMD chips. See www.spec.org and look under the CPU2006 benchmarks, specifically the floating point ones.

Small clusters give good speedups generally, often 80-90% even only on gigabit ethernet networks. Clusters bigger than about 8 processes need to start thinking about higher end networks such as infiniband, myrinet etc.

The best price/performance ratio for small clusters (less than 8 processors) is currently a cluster of high-end Intel CPUs, where the CPU is only half loaded (1 process on a dual core, 2 processes on a quad core).

In conclusion, don't skimp on the hardware. If you are on commercial licenses the cost of the hardware is a fraction of the software so get the best hardware you can to make the most of the large investment in software.

Glenn Horrocks