Which hardware for new tekkit lite (root) server

[DaSoul]

Hey guys,

i'm looking for a new server hoster as right now with 3gb ram and an amd opteron 6128 it starts to lag when building quite some machines,large logistic systems, factories and stuff. (~ 6 players)

What do i have to look for? Better CPU or more RAM? Which CPU is more powerful i7 or xeon? (some hosters offer i7's other xeon cpus)

Thanks for any advise.