UPDATE It was NOT GOOD ENOUGH AT ALL, but a Xeon quad-core rig did the trick!
Anyone have experience with these chips?
So far I've had up to 6 on at once during testing periods and everyone said it performed fine with no lag.
The specs are CentOS, Intel Atom Dual-Core 1.8 Ghz D525, 4GB RAM DDR3-1333, SATA II HDD, 100Mb/s output.
Currently I am only running pure Vanilla, but I wish to add Bukkit and some plugins, and if the server can handle everything, I'd like to put Mono on there for McMyAdmin as well.
Do you think we could have 20-30 players going at once on this rig?
I am not sure how different an Intel Atom in a server is compared to a netbook one, but this server seems to be performing great as a whole thus far.
It's possible that the RAM/MOBO/HDD/NET are making more of a difference and the CPU is less of a factor, but I'm not sure.