i really confused as to what ghz cpu i have in my computer. this isnt going to be anywhere near as good as what you usally get asked about so please dont laugh at how bad it is to much

i have a AMD Sempron 2600+ 1.66ghz. now i was told by someone that the 2600 stands for 2.6ghz but i dont understand why put this and then 1.66 ghz. could someone please solve my query is it 2.6 or 1.66 ghz
thanks!!