Fixed it!   Anyone upgrading from an i3, i5 or i7 to a Xeon:  Don't forget to go into the BIOS and turn on Virtualisation Support!!!   It isn't enabled by default after changing the processor!   Doh! :emotion-4:
Hello,   My understanding is that the VT-d feature present in the Xeon processor is all thats needed to make a host capable of passthrough on ESXi however when I enter the advanced configuration there are no devices listed for passthrough.  The only thing written where the list usually is is the following message. 'Host does not support passthrough configuration' [IMAGE] I would have thought I would be able to see the USB controllers at a minimum available for passthrough. I am running a T110 11G with a Xeon 3440 and 6GB RAM.  ESXi 4.1 Update 1 from Dell's website (i.e. with built in Dell drivers etc).   Am I missing something? Thanks all!  
PowerEdge T110 ESXi4.1 Update 1 (Xeon) - 'Host does not support passthrough 
configuration'