We running a clone server pentium 4, 1G of ram not even a dual processor about 5,000 students around 2,000 are active. Moodle is not only thing thats runs in our server but other hosted websites too (library and stuffs). Our server is also the DHCP server for our client, the busiest server ever. Server crash from time to time.
How I wish we had that server specification.
I think your server is far better compare to mine. We don't have enough money to buy such server so we will stick to clone ones.