I think there is no argument that older servers should be consolidated. I couldn't find any decent studies on moving from Xeon class servers to newer Xeon quad core servers.
Everything seemed to be based on PIII class machines. Anybody have any of those around anymore ?
I wanted to see how a substantial workload on a Xeon 3.06/533 MHz/1MB would consolidate to a Quad Core Xeon 2.66/1333Mhz/8MB with ESX.
I tested three older machine, IBM x345, Dell PowerEdge 2650, and HP DL380 G3 with similar configs as possible. Ran a workload up to 30% on each, and measured performance and wattage draw. Then used VMware Converter 3 to migrate the workloads. Kept adding VMs until I got to 80% CPU load on ESX with same performance as before on the VMs.
I was able to get 8 of these VMs on a single Dell PowerEdge 2950. So 8 to 1 box consolidation story and about 2 kilowatts in power savings.
Works itself out to about $5,000 in savings over 3 years with average power prices, and even more if you're in the NE 
My findings and the paper are here :
http://www.delltechcenter.com/page/PowerSavingsthrough+Consolidation
Interested to here in what others have found through their consolidation efforts.
\- Scott
