Que2,
after some tests these are my results with my ESXi 4.1 U3 installation:
The problem was the hardware:
Asus P8P67 Pro (P67 Express Chipset) with a intel i5-3570K or i5-3470S cpu didn't work with Win8, but with all other systems.
A BIOS update and playing with all the BIOS settings didn't solve my problem.
With my Asus Maximus V Gene (Intel® Z77 Express Chipset) the EXSi could not find the vmfs volumes, but this is a other problem.
What worked with Windows 8 Pro was a old Asus P7P55D-E motherboard ...
thx for your help.
br