Dell published an interesting 16-pages paper where a 2-way Dell PowerEdge 2950 is compared against the new 4-way HP ProLiant DL 585 G2, both running several virtual machines over a VMware Infrastructure 3 platform:
There is a lot of debate these days around what is the optimal hosting platform for a virtualization deployment. Most of this debate is centered around the decision to deploy either 2 socket or 4 socket building blocks as the basis of the infrastructure. In order to illustrate the advantages of using two-socket servers for virtualization over four-socket servers, a test was conducted with VMware Infrastructure 3 on the Dell PowerEdge 2950 and the HP ProLiant DL585 G2.
The results of these tests show that three PowerEdge 2950 two-socket servers can provide up to 44% more performance, 57% more performance per watt and a 95% average advantage in price / performance than two HP ProLiant DL585 G2 four-socket servers.
Read the whole document at source.