Hardware performance from HADOOP cluster

[Usman Waheed]

Hi,

Is there a way to tell what kind of performance numbers one can expect 
out of their cluster given a certain set of specs.

For example i have 5 nodes in my cluster that all have the following 
hardware configuration(s):
Quad Core 2.0GHz, 8GB RAM, 4x1TB disks and are all on the same rack.

Thanks,
Usman