All CPUs have cache built in... they have to have it. The speed of onboard cache makes the fastest memory and FSB or HT speeds look like molasses. I'm not overly familiar with intel's stuff, but Athlon64s have 64KB + 64KB L1 cache, and 512KB or 1MB (depending on the model) L2 cache. Some other types of CPUs have L3 cache, but it's not so common.