Hello ,
Thanks for the help , but it appears that the gang of three ( Microsoft with HYPER-V, VMWARE with ESXi 5.0 , Citrix with XENSERVER ) had
something like an "agreement" . I'm joking . To implement hose 3 features or to virtualize them , one needs VTD IO features enabled on the BIOS.
For the particular case of VMWARE ESX , it's a very peculiar product and one has to read very well the compatibility list it releases for each product.
If you don't tread their line , your setup just get stopped and there is no way to work around.( By the way : ESXi3.5 requires also VTD for Intel Chipset or AMD-V for AMD chipset in addition to the aforementionned ICH7 + Network adapter )
For VMWARE ESX , its a best practice to have at least 2 ethernet adapter card for High availability. Any non recognised card is just ignored and appears nowhere in your environment .
It took me two months to find out a mobo that met the requiremnts for VMWARE ESXi3.5. It still works for ESXi4.1 but nomore for ESXi5.0.
( see reason erstwhile ).
Hope that would help someone and cheers