There are plenty of folks in ALFA who can give you more detailed advice, I just build my own computers for fun and Host Baldar's Gate.
BG is currently running on a dual core cpu (Intel e8400 if I recall) and 8GB of RAM.
I'll swap in an Intel q9550 cpu when I upgrade my gaming rig.
I'd suggest upgrading to at least a quadcore cpu, with a motherboard that can handle 32-64GB of RAM.
CPU LGA 2011 or LGA 1155
RAM 32 or 64GB
Hard Drives: 500GB or a pair of 500GB drives (or a pair of 1 terabyte drives.
)
The 32GB motherboards that can handle an
LGA 2011 cpu are reasonably priced.
The 64GB motherboards that can handle an LGA 2011 cpu are kinda expensive at $250-400.
RAM is blessedly cheap. Amen!
Hard drives? We're doing fine with about 500GB of storage on BG.
Having some more space for weekly backups would never hurt and if RAID will work with the way the servers get set up, then I'd suggest doing it.
It might be worth going with a slightly less impressive cpu, but I think the Intel i7 3820 (see above) would be pretty fantastic. It has benchmark scores about twice as fast as the quadcore cpu (q9550) that I'll be putting into the BG server in a few months.
-Bill
PS. Don't forget bandwidth.
BG is running on a Verizon FioS connection with 25mbps upstream and downstream.