I run citrix in VMware GSX, and I have an identical physical citrix box. Both production. I wish I would have put it in ESX with SMP because the citrix box can only use 1 processor which isnt good(even with GSX dual processor license). I would say VMWare burns 20-30% of the resources(the physical can probably handle 20-30% more connections). The performance problems I see is the physical disk, and mainly the processor. 1 3Ghz processor is only good for maybe 23-25 processes. Overall I do like it though. If my manager messes up the virtual citrix server I just revert it to the last snapshot and its fixed. If he messes up the physical one, I've got a a solid week of redoing it ahead of me. -Jon- .