I built a new HTPC with the new i3 2120 cpu and Gigabyte GA H67MA D2H B3 motherboard.  Thsi was very unstable and crashing /locking up and when reset button pressed it would start then die then start die. After restarting several times it would boot up.  My BIOS was version F1.
  On the Gigabyte website F2 was listed as first release.  Anyway about 2 weeks ago they released a new F4 BIOS. I updated and after over a weeks testing can confirm all problems fixed.  Feels different computer altogether. It is now a very nice machine. 

So my point is if anyone has this motherboard and are having problems, I can advise then to upgrade to the latest bios.