1. Drivers - uninstall & re-install -> http://sites.amd.com/us/game/downloads/Pages/downloads.aspx
2. Memtest 4 passes or at least 1 hour
3. PSU - if you have a failing/bad PSU then under increased load a BSOD can result. IMO test the CPU with Prime95, if you get a BSOD under load then chances are a 'power' problem is the likely cause.