From Health Status:
- VMware, Inc. VMware ESXi 5.1.0 build-799733 2012-08-01 00:00:00.000
- Intel Corp. System BIOS S1200BT.86B.02.00.0040.092620121113 2012-09-26 00:00:00.000
I've also installed a community driver to allow ESXi to use the 2nd NIC on my board. But sesnor data was unavailable prior to that anyway.