every computer is able to run a eo server
but the quality depends on your spects and ram and cpu (and internet)
some of my clients run a eo server on a Quadcore (single core assigned @ 2.8GHZ) and 256 mb dedicated ram
they can have 30 players on it ( average) and then the lag starts because of the low ram
then they go to my basic package ( 512 mb ram and 2X 2.8GHZ cores assigned) and they handle around 100+ players
so as you can see , it depends on your computer spects and what ram/cpu you have
but hd doesnt mather at all , they got 25GB hd and they got most of the time 15GB left (other space is in use by there server files and ohter garbage)
so , depending on your spects will it be a good lagfree server or a crappy server
but it will always works
Greetings From PowerChaos