It's not out of norm.
I am running the stock fan - and have a C0 step i920. My cores idle around 40 degrees - and when I maxed out the processor with Prime95 to test my components after the build - the temps hovered around 80 degrees for all 4 cores.
I'll eventually replace my stock cpu fan later on - but right now - I'm so far from fully utilizing the processors on my PC - it's not even enough to worry about for me.
I would suggest you not run Prime95 anymore until you get an aftermarket heatsink and fan. 80c is pushing oblivion.
40c is fine for idle temps though.