cpu, ram or bandwidth -- what is most important for bitcoin mining? [I know Bitcoin mining on a server is a losing proposition, consider this an academic question.]

I've got some old proliant rack servers and VMWare licenses and thought I'd put them to use mining.  In setting up the VM I can alter cpus, ram, and network.  (I'm stuck with 10k rpm HDDs.)  My question is which of these is most important for optimizing mining?

My guess is CPU followed by RAM but interested in thoughts here.  thanks.
CPU is basically the only thing that matters.

The memory requirements for mining are trivial (enough to run bitcoind; SHA256 uses only a few bytes of memory).  Having more that enough will add no benefit.  Disk performance is nearly irrelevant also.  

A fast network connection may help you get new blocks a little bit faster.  This is helpful because the time in between when a new block is released and when you get it is effectively wasted mining time.  But even with a very slow network connection, this should be at most a few seconds.  With a 10 minute block time, the difference between the slowest and fastest network connection should impact mining efficiency by less than 1%.