The idle temps are a bit weird, but as said before, its the load temps that are important. Good that you have a new heatsink on the way, as that will drop the temps a bit and might even them out. Part of the reason that the idle temps are so different could be that the stock heatsink may have a slight warp in it, thus not making sufficient contact for even cooling. But even with a top grade heatsink, you'll see temps vary between the cores. I have a TRUE, which I lapped, and my QX9650 varies about 5c between the cores, so I'd say the variance is normal.