The K63 is a .25mu process K6 chip that has 256k of on die L2 cache. The K63+ is a .18mu process k6 mobile chip that has 256k of on die L2 cache. K63 topped out at 450mhz(I think) the K63+ officially tops at 600mhz(again I think). For a SS7 system its a pretty good upgrade if you can find one and it is supported by your motherboard.