I have researched this and there appears to be no advantage to using server processors over desktop processors for minecraft unless using out-of-game features like dynmap or other plugins which run on their own threads enough so to justify buying more cores. You could even call it a disadvantage because of the wasted money. Although MC uses around 63 threads its still mostly a single threaded engine. It seems like having more than 4 cores is completely pointless, and the real bottleneck is CPU and RAM clock speeds. Server processors are meant for when you have a very large number of threads and need as many processing cores as possible, while MC will almost never utilize more than three.
I recommend getting a high clock speed quad core such as a Vishera for only 120$ and liquid cooling and overclocking it to around 4.5GHz, which would be nearly twice as fast as processors people use and for 1/5 the cost.
I may be wrong however, but everything I've read and experimented points to this. --Khlorghaal 04:28, 10 May 2013 (UTC)
Why is the 4930K rated higher than the E3? They're both basically equivalent in singlethreaded performance, which is ACTUALLY STATED IN THE ARTICLE as making the only real difference on server performance.