the speed went down because the processor is set to power saving mode. when it's idle, the clock speed goes down to save power. you can run a benchmark or a cpu intensive program to make sure that it goes all the way up to the speed you should be getting. for example my phenom II 955 clocks back from 3.2ghz to 800mhz to save power. if you want to change so that you it shows full speed all the time (more energy use and heat) you can do that in power options. change it from minimal power or whatever it's on to home/office