It also introduced the use of virtual memory . Neither the 80486, Pentium, or later processors introduced any new modes of operation. Back to Top Clock Doubling Starting with the 80486, a trick called clock doubling was introduced. Microprocessor manufacturers found that they could make processors that ran at high clock speeds, but most motherboards only ran at a maximum of 33 MHz. Therefore, clock doubling was introduced.
Clock doubling uses a specific multiplier to increase the internal clock speed.
With clock doubling, processors could run at one speed internally, and another externally. Starting with the Pentium, most motherboards were increasing in speed to 66 MHz. In the Pentium II, the maximum speeds are around 400 MHz, and with new 100MHz motherboards becomming popular are still increasing.