only the second and the fourth server on your links (with Supermiro 370DLR and Supermicro 370DER motherboards) have slanted angle memory banks on which this CPU will fit well insider the 1U case. About the other two, you need to be very careful since even if it does fit inside the case, you may only have about 1 mm of clearance. Since your server will be racked with other servers, I will just worry a little bit that the weight pused down by other servers may give you some problems....
So Ask VO to get you the 370DLR and 370DER motherboards, and you will be all fine
Woa ... a system with 4GB of memory
I like it
I am building my own system with 2GB of memory, and I thought it's quite a lot of RAM already, at least for me