[jensnockert]

The problem in HPC is less often pure CPU horsepower though, it is often cache or memory bandwidth, or in the interconnects.

I guess you might be able to build a system in the cloud to provide TOP500 level of performance, but it would be pretty hard even with the fancy EC2 HPC instances (http://aws.amazon.com/ec2/hpc-applications/).

[nwhitehead]

Thanks for pointing out the HPC instances that Amazon has. A few commenters were saying that it's not really a supercomputer without a fast interconnect. Yes, they have that! You just pay more for those instances.

In my experience Amazon did a pretty good job setting things up. It's fun to play around with HPC instances, you can get some sweet performance.

[quail_bird]

better than might... you can: http://www.top500.org/system/10661

[adestefan]

Amazon can. That has no information about how the nodes were allocated. They could have hand picked X rack of nodes that were all connected via the same switch, etc. You don't get that guarantee from AWS.

[quail_bird]

Fair enough, I guess.... they could have done many things.

Although they do not provide an answer, here are some links to additional info - I spent some time searching for additional info on the Top500 setup, but found little:

* http://aws.typepad.com/aws/2010/07/the-new-amazon-ec2-instan... * http://news.ycombinator.com/item?id=1904590