One of the problems with the new servers I've bought is that I'll have to pay for the costs of running them, and we all know that the running costs in terms of electricity are not cheap.
Using lower energy machines (but with the same CPU power) such as the T1000 is one solution, but it's always possible. However, that drive towards low-energy computing is producing some interesting side projects, like the new 1W x86 CPU from VIA. Here are some resources if you want more information: