I just put my new build together and am wondering about my cpu temps. I have a e8400 and an artic freezer pro7. I used the paste that was on the heatsink if that helps. Core-temp is showing 42-46C, Realtemp shows 32-35C and Asus probe shows 38C. All temps are at idle. Im hoping to overclock for my 1st time and want to make sure my new system is up to speed before I start.

Just to clarify, you have 3 sensors.

Tcase - sensor between the cores or IHS temp.  That is what your bios, and perhaps Asus Probe is showing.

Tjuction - has a sensor on each core, also know as a DTS sensor, which realtemp and coretemp display.

Now CoreTemp and RealTemp go by a Tjuction max temp, and they are different, hence why you have different readings.  Intel won't publish the Tjmax, so all the programs that can read the DTS sensors, the programmer just assumes what it might be.

Chances are, your best off going by the Tcase temp.  The E8400 Thermal Spec is 72.4C.  I'd say as long as you keep that temp below 69C, you should be okay.

Edit:

I'd test a prime95 load to see how hot it gets a stock.

I would go with realtemp readings.

Realtemp has it at 51C with prime95 running at 3.6 overclock. Hows that so far?

I got Big Typhoon on E8400, and i get 32, and 38 when overclocked @ 4.1
So the temp is fine