Question : esx 4 update 01 no 64bit server will install

Wierd one

I have a an esxi 4 update 01 server installed on a dell poweredge 1850 and no 64 bit m$ server 64bit os will install. I know the 64bit os's where experimental in esxi 4 but as esx 4 update 01 has 64bit servers in its list when your setting up a vm.

In short the problem is setup fails and says a 64bit cpu is required, I can confirm the dell pe1850 server is 64bit as esxi 4 will only install on 64bit cpu's. I had the same issue installing ubuntu 64bit linux

Answer : esx 4 update 01 no 64bit server will install

The Dell Poweredge 1850 uses an older P4 Xeon which, while supporting native 64bit OS's (i.e. 64bit W2k3, 64bit Linux, and ESX4 hypervisor), doesn't have the VT instructions which are a prerequisite for 64bit VM support. General rule of thumb is you need a server with either an Intel Xeon 5300 series+ or AMD Opteron 280 series+ CPU to run 64bit VM's.