Despite all the new technologies to reduce processor power consumption, the processor and LCD monitor are still the highest power hogs on a laptop, especially when the processor is working hard and the LCD brightness is high. Heat is not a problem for the LCD as it has a lot of surface area to lose heat, so it never really gets hot (at most also only at where the inverter is). But processors have to lose close to 50W of heat (at full load) from a surface as big as a fingernail, even with heatpipes its not that easy to dissipate the heat rapidly enough to prevent temperatures from reaching uncomfortable levels (uncomfortable to your lap, that is). Some parts of a laptop's base will get irritatingly hot while the rest remains lukewarm at most. Implementing a liquid cooling system would help, but the problem still remains that it would increase the size of the laptop noticeably. Even in "desktop replacement" laptops (like the Dell XPS) which are easily big enough to fit a minaturised liquid cooling system, its still not a good idea as coolant is pretty dense and will significantly add to a"desktop replacement" laptop's already hefty weight