Well I have owend a pentium 3, core duo, and a 2010 p6100 laptops. P3 was the hottest, core duo used to burn my legs, but the p6100 is really cool. The fan never turns on. Only when I play games it turns on at low speed. Bottom of laptop is only slightly warm. Really low temperature cpu. My question is that sandy bridge even more cooler?
However, many of the Sandy Bridge mobile chips are dual core, not quad core, and run fairly cool. The quad core mobile chips do run warm, but they have a greater range than earlier chips because they can idle lower, and accelerate when needed.