Texas Instruments 486 Microprocessor
In 1989, the 32-bit 486 heralded the fourth generation of microprocessors with two radical innovations: the integration of the floating-point unit on the same chip as the processing circuitry and the addition of an internal 8-Kbyte memory cache. With 1.2 million transistors on an 81-square millimeter die assembled with the available 1.0-micron complementary metal oxide semiconductor (CMOS) technology, this microprocessor took the world's PC markets by storm. This central processing unit (CPU) initially had a clock speed of 25 MHz running on 5 volts with a maximum power dissipation of 5 watts. There are many models of the 486 processor including those featuring clock doubling and tripling, and embedded and low-power versions, making the family larger than the previous 386 family.