I recommend everyone including System Stability Tester 64-bit in their test toolkit. it helped me to reveal that 1,35 vNB wasn't enough for Q9450 to work at 440*8 (almost immediate BSODs with various stop-errors), while all other test programs were stable (including monstrous Intel Linpack 64-bit). I had to increase vNB to 1,39v and now everything is OK.
http://sourceforge.net/projects/systester/