I'll explain the cpu cache then.
Your processor process all the mathematical data through your computer (the exception being graphical and if you have a sound card; audio). It can only hold so much information within itself at once. This is its cache. The rest it stores in your RAM for safe keeping, and then if that fills up it stores it in the paging files of your hardrive. As information passes through your processor it moves from the paging files, to the memory, to the cpu cache, because the cpu cache is the fastest type of memory in your computer. Memory comes in second, and paging file third. The more "powefull" the processor is, more often times then not the larger cache it has. Larger caches and more cores allow your computer to handle more information at once, great for complex programs and multitasking. Get it?