Because the L2 and 128 which are the memory buffers built onto the CPU. They vary from brand to brand in size and speed. When it says not applicable, older CPU's don't have that built in cache. Built in cache is like a holding tank for information, makes it faster. This is from my DH. He use to sell computers and repairs and builds them on the side. For example: you are typing the number 1, the computer would anticipate your next move and store in L2 the numbers 2-0. So, that it speeds up the process of typing the actual numbers that follow the number 1. A processor does over a million calculations per second. Clear as mud? If you have any more questions, feel free to PM me and I will ask DH. I am not to good on the workings of a computer. He is the hardware person and I am the software person.