If I boot into my bios, the CPU idles at about 36-38°C. Which is consistent in Hardware Monitor. Now, the core temps are all lower. Anywhere from 21-26 idle or under a light load.
I'm using the stock AMD heatsink and fan that came with the chip. I have 1 front 120mm fan pulling in. A side 80mm blowing out, and 2 back 80mm fans blowing out. To my best guess (there's no central ac in this room), the ambient temperature is around 25-28° celsius.
Here's a picture just running chrome, Core Temp and the hardware monitor.
And here's a picture with Prime95 putting a full-load on the CPU.
It took about 20-25 seconds for the core temps to drop back down to the "normal" reading. About a full 90 seconds for the CPU temp to come back down.
In case you miss it in the pics, it's an AMD Athlon II X3 460, running stock at 3.4ghz, with the stock cooler. I don't know a whole lot about computer temps. I just want to be sure I'm not letting it get too hot.