The site is very slow...

[Buzzfuzz]

It's pretty fast, but not always.
Sometimes there are moments it sort of 'hangs' a bit and no my internet is fast enough @ 120/10 Mbit.

[Buzzfuzz]

Hi,
 
It has been sort of slow lately, probably because they are using a mac as a server. It probably would be faster if they upgraded to a C64.
 
smerf

I think if you have a good Core I7 or Xeon combined with some fast SATA hdd's or SAS's and a stable connection with some upload speed, you should be good.
vBulletin isn't that heavy to run, even if it has a large DB.