thats pretty cool, so temp isnt your wall. 30 minutes on prime95 isnt terrible, you are close. if anything your voltage is too low. ive heard of people upping their voltage into the 1.5x range for 3.8ghz on your cpu but thats a lil high imo. try 1.45, 1.46. see if you can get it stable.
crank the voltage as high as you want cause then you will have a reason to get a SB based rig.... lol but kidding aside i second what everyones has said. the big factor you need to watch is your temps. if your temps are really good then the amount of volts isnt as big of a factor. remember your fighting the heat not the volts.
I be honest to test rigs to see if the OC is safe I prefer to know it is completely stable so I do 24h tests before I am happy with the settings and leave it be.
As for the voltage back when I was reading on how to overclock I learned Voltage and Heat killed hardware. Voltage was one of the killers, but it also generated heat when you apply more of it. So handling the temps alone weren't the only concern the voltage is also a concern, and is also directly related to heat so try to keep that in mind. Hope that made sense.
Short way to look at it: Increase Voltage = Increase Heat
Increase Voltage = Less CPU Life
Increase heat = Less CPU Life
Increase Voltage/Heat = Even Less CPU Life