A client of mine had a very interesting problem, they have been moving their Citrix farm from physical to virtual with little to no issues, P2V’ing servers left right and center on ESX 3.5.
Now they have recently installed a vSphere infrastructure and decided to migrate a few Citrix servers to the new machines. now here is the rub. on 3.5 they were getting 15 -20 users per vCitrix server. (dual vCPU server 4GB RAM). Now when they installed these same servers with the same setup on the vSphere environment they found that the same server was only getting 5 users before grinding to a halt with 100% CPU. well it seems the only difference was the virtual hardware, those on the 3.5 servers were obviously on version 4 hardware and those on the vSphere were running version 7.
We created a machine with version 4 hardware installed the Citrix Image and ran it on the vSphere servers and low and behold everything was running as normal. It seems that Version7 hardware is not compatible with Windows 2000 Advanced server, causing CPU issues.
Well it seem that the support matrix has changed we all know that NT4.0 has been dropped from support, but closer look into the HCL shows that Window 2000 support has been reduced to single CPU.
So I recommend that if you need vSMP on Windows 2000 then utilise version 4 hardware.