Actually Intel chips are since long RISC based, with a CISC translation layer. The real difference is in the more advanced pipeline, prediction and cache and and of course the 32 vs 64 bit + other architectural features. Hence the intel chips use a lot more power than an ARM based processor.
This is not exactly true. In most cases intel's chips are more power hungry but the low power atom processors bring better performance than an ARM cortex A9 while still having lower power consumption. (mostly by racing to sleep faster) And this is a three year old architecture i'm talking about.
