I hv dg41rq mobo and e5400 cpu. Today i overclock my email@example.com(stock cooler) by using setfsb and run stress test (prime 95) and found my oc is stable. Under full load my cpu temp goes upto 80c .
TO decrease the temp i just lower my voltage to 1.1250(using crystal cpuid) and overclock to 3.0 ghz now my max temp under load is about 70c-72c is this temp harmful for my cpu.
From what I've seen your TJMax is around 100C (not positive, you will have to confirm that) which gives you ~30C of headroom. That is workable as an everyday OC but you might want to bring it down a little more if you plan to keep it running with load for any great lengths of time (36+ hrs). I don't think those temps are terrible (nor harmful) for short term usage (ie. 3-5hrs gaming, or video work or...) nor will your CPU ever run at 100% during normal PC usage.