Question : Processor upgrade

I have a HP ML150 G6 server with an E5504 proccesor.

I also have a HP Z600 workstation also with an E5504 processor.

Im looking to upgrade them.

Im looking at E5560, X5560 and E5660.

What i want to know is if all of these processors are compatible with my machines and also what are the differences between the 3 processors.

Thanks

Answer : Processor upgrade

From http://h18004.www1.hp.com/products/quickspecs/13249_na/13249_na.html

Quad-Core Intel® Xeon® E5500 processor series, up to 2.53GHz
Dual-Core Intel® Xeon® E5500 processor series, up to 1.86 GHz