Intel released the Pentium Processor on March 22 1993. The processor was a 60 MHz processor, incorporated 3.1 million transistors and sold for $878. The first Pentium microprocessor core was code-named “P5”. Its product code was 80501 (80500 for the earliest steppings). And there were actually two versions, specified to operate at 60 MHz and 66 MHz respectively. It also came with an unknown math bug in it, which was finally acknowledged by Intel in 1994 and they issued a recall. The Pentium chips included a floating-point unit (FPU) also know as a math coprocessor, while previous Intel CPUs did all their arithmetic using integers. I have been unable to confirm it, but I think it was the IBM PC and then adopted by the clones.
IBM PC had an 8088 CPU and came out in the early 80s. So that’s not it.