Yes, i don't think that the Community Driver has any impact on this - i get the same results on the DQ77KB and DQ77MK Lab's which have exactly same NICs (Intel 82574L - which is idenfied by VMWare ESXi at install time - and the 82579LM which isn't) as your Intel Beartooth Pass Serverboard.
IMHO (I've said this in other threads) the S1200BTL shouldn't be on the VMWare HCL because VMWare don't provide support for the Intel 82579LM NIC......but the community driver is a good workaround.
The latest ESXi 5.1 build is 914609 which I'll apply to my above labs and see if there is any change to sensor data and will post the results.
btw, I'd update the BIOS to 41 - there is a known issue with packet loss on the 82579LM - which was identified and resolved by intel - some people have reported issues here with ESXi 5 with this Intel NIC independent of the driver......