Not all 060 variants are full 060's, either. The ones with the highest clock speeds, up to 75 mhz are all stripped down models the equivalent to an LC in the 040 line, so to get full functionality, you have to go with a slower chip, I think the 50mhz version was the fastest to have both the FPU and MMU on chip. At that speed, the performance difference over a chipped 040 isn't worth the expense.