I was reading a bit on the ARM architecture the other evening, found this in a Wikipedia article. I thought, only 35,000? Wow! Contrast to 1.4B transistors in Intel's Ivy Bridge chips. Not exactly an apples-to-apples comparison, but the gap in performance is much less than the transistor counts might lead a person to believe.
Using the RISC approach, the core ARM processor requires only 35,000 transistors, compared to the millions in many conventional processor chips, resulting in lower power usage and making it very attractive in smaller devices.
I've often wondered about the ATtiny and ATmega chips, but have never seen a transistor count for them.