They probably are. Both cores are +/-2C of each other when under equal loads which is often not the case with 45nm processors. It is quite possible that my IHS makes poor contact with the cores such that both cores still remain the same temp as each other but higher than they otherwise would have been. I have done the razor blade test and the exposed side of the IHS is not convex/concave to any significant degree (I won't go as far as saying it's flat, because they're never really flat). I've reseated the cooler a thousand times (and my cooler is a real pain to do it with), and used both stock and aftermarket coolers with similar results. The only thing left to try is a proper cleaning off of the TIM. The last time it was properly cleaned was in the fab; I've never put a drop of alcohol on it, I just clean it with a rag until no more TIM rubs off. I wouldn't think I'd improve my temperatures by 20C+ though.