Actually the 8942 was insufficient on my 2.4c@3.5ghz with only 1.58v on an abit IC7....problem is that the mounts were for only am 80mm fan...To really start cooling these things at high levels you need decent case cooling and 92+mm fans pushing about 40-50cfm...Deltas are ridiculous...I got a swiftech MXC400 and used a panaflo 92mm fan (quiter then my 80mm and pushed more air...)
I see you list prime95, but unless you are running 2 instances of it, or another cpu intensive app such as prime95 in conjuction to the 1 instance of prime95 you are not seeing the highest load temp.....
Up to 1.65v is fine for the northwoods but make sure cooling is sufficient....Abits undervolt...MIne would be set to 1.625v and it would be actual of 1.58v....so beware of that....
I actually think temps (50c) if legit are not baxd and you have some room to push further....
Stability with an HT cpu without running multiple apps to stress HT is a waste. You may not be as stable as you think...