In 1999, AMD Athlon became the first x86 CPU that was able to do both an addition and a multiplication during one clock cycle, for the 80-bit x87 floating-point numbers.

The previous Intel CPUs of the P6 family, from Pentium Pro to Pentium III, required 2 clock cycles for that, i.e. they reached at most half the throughput of Athlon at the same clock frequency. And Athlon had an even higher clock frequency.

So the launch of Athlon was one of the greatest jumps in floating-point performance per socket in the history of x86 CPUs.

It had a higher clock frequency than any Alpha. IBM POWER CPUs could do much more per clock cycle than Athlon, but their clock frequency was much lower, so Athlon was still faster.

One year and a half later Intel launched Pentium 4, which could match the throughput per clock cycle of Athlon, but only when executing new SSE2 programs, not when executing any legacy program.