I was bored and decided to see if I could push it further...
Got it running with 425 fsb now giving me 3.6GHZ on the cpu at 1.25v
Memory is at 1360MHZ at 1.6v
Ran Prime 95 for an hour and it got up to 56C so not anymore heat than 3.5 was
Ran OCCT Linpack test then went out to get an ice cream. When I came back it had stopped at around 40 minutes and windows said the program crashed. OCCT said there was an error detected but I have no idea what the error was.
I reran OCCT and it went the full hour with no errors this time and the max temps were around 67C.
I'll probably play it on the safe side and just leave it at 3.5GHZ since I really don't need that little extra speed and plus I'm not sure what happened with OCCT while I was gone so better safe than sorry.