A quick look at Wikipedia ("List of Intel Pentium microprocessors") shows that top-of-the-line desktop CPUs ran at 200 MHz, while a current Core i7-6700K is clocked at 4 GHz. That's already a 20-fold increase. Also consider that clock rate is not everything. The number of instructions per clock has also risen, although I don't have hard numbers at hand that easily.
Also consider storage. RAM clock speed is slowly, but steadily increasing, as are cache sizes across all levels. And the biggest gains in this area are made by transitioning from HDDs to SSDs, although I don't have numbers on this one, either.
But the elephant in the room is floating-point performance. The GPU in my desktop PC (a 2015 AMD R9 Nano) does 8 teraflops. Compare with an Nvidia RIVA 128 from 1998, which did 5 gigaflops. [1] That's more than 1000 times faster in just 17 years.
