I'm running a 550 , unlockable like yours...(though currently I'm actually only running two cores,stock speed, undervolted at 1.2 volts, 3.1 ghz, simply because...what I'm doing and playing right now has no need for 4 cores) with the stock fan.
A couple of points, configure speed fan with the configure button...that way you can be more sure that the temps are what they indicate they are...
My temps are as follows , at idle,
the first core corresponds to the CPU...the second also to the GPU temp...for some reason.
When I had all 4 cores unlocked I couldnt get any temps reported on the cores...or rather nonsense numbers if i recall correctly...-273 c...etc Via overdrive if remember correctly...
Also...if you're going to be overclocking, I'd suggest you follow one of the guides around here on Tom's...Overclocking via programs usually doesnt carry over with a computer reboot.