The 8086 was an early PC processor that was slightly more powerful that the 8088. It came in 5, 8, and 10Mhz variants, and had a 16-bit bus, where the 8088 only had an 8-bit external bus (both had a 16-bit internal bus). It was released on 6/8/78. (The 8088 came out about a year later, and it's slower. Go figure.) The processor had 29,000 transistors (3 micron). It could use the same 8087 math co-processor as the 8088.