I switched my stock HSF to the 212+ Cooler, now my idle times are way down.
I used to idle at 20-25c and 58c on load. Now my CPU idles at 8c-15c and 26c on load.
Either the 212+ Cooler is a miracle worker, or the temp readings are suddenly off.
I have an AMD 1035T @ 3.1ghz. I actually have the same OC, since the cooler temps still won't let me overclock more.
I'm guessing OC is being limited by my cheap mATX mobo.
What program are you using to look at the temps? Temp sensors CAN go bad over time, or they could have just have been wrong to begin with, but simply changing the HSF shouldn't cause the sensor to go bad by itself. My suggestion would be to try as many monitoring programs as you can to see if they all agree (Core Temp, RealTemp, HWMonitor, SpeedFan, the software that came with the motherboard (preferably its updated equivalent), and even OCCT, even though that's not its main function, it still gives you temp readings).
I've used Core Temp, HWMonitor, and Argus Monitor. All are giving me the same temperature readings within 1c.
I'm planning to buy a better mobo in hopes to over clock more. Hopefully that fixes my temp readings.
Edit: It's actually CoreTemp not RealTemp as I stated earlier