hanks for taking the time to submit details about your working ESX/ESXi whitebox. If you could please include details about your hardware such as the items below if applicable. This will make things easier for others who try the same hardware.
- server / MB / NIC / controller make and model
oem board, Precision 490
- chipset
Intel 5000x
- CPU socket and type used
Dual E5120 Xeon
- BIOS / firmware versions
latest as of 12/31/2011
- are the onboard NIC / storage controller working
yes
- any changes required to enable ESX/ESXi to recognize hardware components
no
- does the storage controller support RAID / battery backup for write cache
yes - but my battery is dead so it disables automatically
- does the MB support Intel VT (vt-x) / AMD-V
yes
- does it support vt-d (directed I/O) / AMD IOMMU (http://en.wikipedia.org/wiki/X86_virtualization)
unsure
- is the CPU FT (Fault Tolerant) capable - use the following bootable ISO image to check this - http://downloads.vmware.com/d/details/c ... R0dGhidGR3
unsure

Extra Details:
MR10i Raid Controller pulled from IBM Server
4x7200.10 1.5tb seagate drives in raid10
2x30gb core v1 ssd from OCZ (use this to create small vmdks to host pagefiles for servers to reduce disk contention, very effective)

I've run 4.0 4.1 and 4.1u1 on this setup, no issues.