up to 70c-75c under full load for an extended period of time with the stock cooler, and
everything in bios set to auto seems to be par for the course with the 920.
these higher temps are usually hit when your cpu goes into turbo and the auto vcore goes up to probably 1.25 or higher and then stays there for awhile. (like 3 hours of gaming)
also, the room temps, and your case air flow are important and can change the effectiveness of the stock cooler.
last thing is that each individual chip is going to have a different voltage tolerance and if you have a chip that is unstable at lower voltages, than your VID signal is going to send a higher value to the mobo regulator and you will end up with a hotter cpu.
look at the intel data sheet on the 920 find it here...
http://ark.intel.com/Product.aspx?id=37147
and find the information on the VID and the PCU; intel made changes to the voltage signaling because of the onboard memory controller.
I have also read that beacause this is a new feature, intel has not ironed out all of the manufacturing processes, and it is resulting in a greater variance of CPU and onboard memory controller voltage tolerances. (i think it was in an anandtech article, anybody have that one?)
i am getting the same temps as krypto1300... and i am overclocked to 3.2, but i manually lowered my cpu voltage to 1.045v.
but your chip may not be stable at that low of a voltage, they are all different.
but, basically, i don't think you have a problem at your current temps.