A lot of things affect temps. The chips could just run hot, high ambient air temp, case air flow, heat sink design, proper seating of the seatsink/thermal material, and more.
Do easy stuff first.
Examine your case for air flow obstructions. See what you can do about room air temp/air flow, if its an issue.
Drop your system back to stock and see what temps you get then. Do it in 200 Mhz increments and see what temp reading you get at each speed. If its still a little high at each speed, you might have a hot running chip or a heatsink/thermal material issue.
Better heatsink would help, but I would try that last.
However, my guts says something is wrong with the heatsink/thermal material. 1.25v is not very much. Temps seem awfully for that voltage setting.
every one has a different opinion on it but i dont run prime 95 as it puts your cpu under stress it not going to see in real life use
to me my overclock is stable if it doesnt crash when doing the stuff i normally do like heavy gaming and video encoding etc
those temps dont look seriously bad--you could change your heatsink if it bothers you
There's something to what your saying, but it's not the full picture. You can be slightly unstable depending on what your running and not crash. Now that's great if you don't crash, but you will over time corrupt data on the drives. If your one one of those people that format often, then it's not a problem. If you don't, then making sure the system is fully stable is important. Just my 2 cents.