I felt this deserved a separate post as the issue could have driven me crazy/made me return the motherboard in error!!!

After building the first server for my new Virtual Lab i installed ESXi and started to deploy my first VM. Everything was going nicely until vSphere lost the connection to the server. I used the IPMI remote control to take a look at the console and apparently both network interfaces were disconnected? Maybe something went wrong somewhere…

Reboot… Same problem after 5minutes or so the network connections drop
Reinstall ESXi… Same problem…
Recrimp a couple of new network cables… Same problem…

Finally i found this article which quite correctly identifies Active State Power Management as the cause! Pop into the bios:

Advanced, Advanced Chipset Control and disable Active State Power Management

Voila! Everything’s now chugging along nicely (fingers crossed)