Intel 486DX Microprocessor

In 1989, the 32-bit 486DX heralded Intel's fourth generation of microprocessors with two radical innovations: the integration of the floating-point unit (FPU) on the same chip and the addition of an internal write-through 8-Kbyte memory cache. With 1.2 million transistors on an 81-square millimeter silicon substrate, the chip was photolithographed with 1.0-micron complementary metal oxide semiconductor (CMOS) technology and was a tremendous advance over the reigning 80386 central processing unit (CPU).