Upgrading CPU's in a Dell PE CS24-NV7

Hi All,

Im not new to building PC's, however im new too servers, I just bought my first ever rack server (Dell PE Cs24-NV7), ive seen only one review saying it is loud and wastes power, however that doesent bother me, as its dual cpu, default configuration I bought it in looks slow from my end, I just wondered if I could upgrade the CPU's in it, it has the following CPU's in it :

Processor: 2 x 2.1 GHz Opteron (2373) Quad Core

they run at about 90w's each, I want to buy these cpus for them (I think 125w's per cpu)

AMD Opteron 8389 Quad Core CPU 2.90GHz Socket Fr5 (1207) OS8389WHP4DGI

The PSU for the server is 600w's, I have 4 x 250gb SATA hdd's (3.5), Im unsure about how much the board / ram and hdd's pull together so I thought I should ask if this is a wise purchase as I can get a bunch of these second hand, they seem to be the same socket type etc so will the psu run them (Two of them, or do I have to upgrade the psu) ?

Thanks for any advice on this !