Intel/MS uses a System Idle Process which consumes time in a loop which is prepared to yield to any other process when interrupted."For example the CPU could be sitting there idle"
That's because clock rate is not the be all and end all. It depends on what you do with each clock cycle. There are quite a few variables. You'll probably go over pipelining next so here's just a little illustration of the point.For example she said there's an 800MHz Sparc that out performs an Intel Dual core at 2.2 GHz.