Well uber, yes and no.
On windows, mac or even linux, most of the time you have a lot of stuff running in the background which of course, takes up some or a lot of cpu power.
While on a console, only the game and the simple OS is running which gives the console more time to focus just running whatever game you're playing.
Also, one of the most important aspects in discussing the difference between PC and console is that when developing a game for a console one has fixed set of specifications, be it the cell and a Geforce 7900GTX for the PS3 or whatever the 360 is running, the developes usually don't need to worry about how well the engine they're using or creating scales, because of the unchanging specifications of the console.
This as opposed to developing a game for the PC or mac where you as a developer may have to deal with multiple graphics chips, CPU architectures, mutli operating systems, let alone having to deal with engine scaling to make your game compatible with the widest array of systems.

EDIT: btw kunaak, not to be a pain in the back or anything, but it looks to make as though comparing the pc to the console a whole lot right there