ARM-based chips (like the A10) tend to have a much smaller thermal envelope and much less battery draw. They were built ground-up for mobile use, while x86 was

ARM-based chips (like the A10) tend to have a much smaller thermal envelope and much less battery draw. They were built ground-up for mobile use, while x86 was built for speed & power. I can't think of many fanless x86 laptops -- the only one that comes to mind is the current 12" Macbook, but that makes a ton of compromises and is running a CPU that's basically 5-6 years old. On the other hand, the idea of a cell phone with a big heatsink and fan assembly is laughable.