What's the difference between real memory and CPU, and what are there effects on the performance of my computer? In Activity Monitor, there are a couple fields: "PID", "Process Name", "User", "%CPU", "Threads", "Real Mem", and "Kind". I'm not familiar with the inner workings of computers and the related technical terms, but I've always thought the "%CPU" and "Real Mem" would be synonymous. However, when I look the running processes in Activity Monitor, I see this:

 

Evident from the image, "Real Mem" and "%CPU" are not synonymous.

What's the difference between real memory and CPU, and what are there effects on the performance of my computer?
CPU is the Central Processing Unit. It's an Intel microprocessor. It performs calculations (or more precisely, computations).

Memory is temporary data storage space used by active processes being executed by the CPU.

If we were talking about cars the CPU would be the engine and the memory would be the seats (or possibly the cup holder).