You got your multipliers backwards with the 486dx. The multipliers was on the CPU core rather than the bus. A dx2 was twice the memory bus speed. The dx4 was (c

You got your multipliers backwards with the 486dx. The multipliers was on the CPU core rather than the bus. A dx2 was twice the memory bus speed. The dx4 was (confusingly) three times the bus speed. So a 486dx4/100 was a 33MHz bus with a 100MHz core.