Post: #5

UO Servers does not consume too much resources, they can fill your RAM but does not exceed your processor capacity.
There is a Brazilian Sphere Server (Dimensions) that is a 12Gb RAM and QuadCore Xeon 2.13ghz that runs 80-120 players and I bet they are not using 20% of their server capacity (Coruja can tell exactly what is going on the server)

Cutting-edge servers may hold about 1000+ players with no problems.
The main disadvantage of Sphere is it script-parser, it does use too much CPU.
UOForever (RunUO server) once hit 997 players, with 500-600 daily.
Official RunUO Servers claimed they've hit 3000+ players back in 2005 and I've found a post on UODEV.de saying that they hit 7891 players in 2004.

Back to Sphere, I never saw a stress test, but the scenario should not be different
The Abyss Sphere hit about 250 players, and if I am not wrong, they use Sphere 0.51a, a very very old sphere version on a 12x4GB 2xXeon Quad-Core.
I used to home host a 30-40 players sphere server back in 2004 on a Pentium3 700mhz and 512Mb Ram with no performance issues
So, do not fear about not having the resources, UO servers does not consume too much resources