trt740: lapping only helped me since my CPU and my heatsink were both convex. my cores had a 10C difference between core 1 and core 4 - lapping reduced that. i believe lapping the CPU made the most difference. inferknox: you can use any fan with a xiggie. they use a funny little rubber mount, but thats transferable to any standard fan, and you could always resort to zip ties.