Originally Posted by screwtype
No it won't. Later model CPU's have much more efficient architecture which more than makes up for lower clock speeds.
As I understand it, higher clock speeds mean more heat, and CPU development has hit something of a wall in that high clock speed CPU's are harder to keep cool. Some late model Pentiums for example have had overheating issues.
It's partly for this reason that CPU manufacturers have stopped concentrating on just cranking up clock speed in favour of more sophisticated solutions, ie better architecture. This way they can keep clock speed, and thus heat production, down, while actually increasing overall performance.