TJmax on that CPU is a 100 C I think so you could probably do 4.5 - 4.7 while bumping around in the 90Cs.
That's if you get NO errors in Prime95.
Be sure you are not getting a Core Stall on one of the cores by checking Task Manager also while O/Cing.
Sometimes RealTek Audio Manager running in the background will cause a Core Stall and keep temperature artificially low and you won't know it unless you check the graphs in Task Manager during O/Cing.
I use Real Temp and just setup the systems to run at 4.5 - 4.8 when called for.
4.5 is a good O/C because above that, most of the time Prime95 will start having errors which means the CPU is not operating at 100% pure condition.
Rick, I really don't want to go any higher. I started out thinking maybe 4.1 or 4.2 but it worked so well I decided to kick it up to 4.5. Like you know, the more heat, the more ware & tear on the cpu. I used offset voltage so it drops back to around 36C under normal use. But thanks for your post.