Over that time CPUs have also increased their instructions per clock by 3 to 4 times, so the comparison is a bit closer than that. 5Ghz in CPUs is also common these days which would make it even closer. RAM has also improved in more than just total size though.
This nerd sniped me a bit. Your calculation on the amount of CPU power is too low, because of the change in IPC, but for the things we have benchmarks for, it isn't multiple orders of magnitude off like I expected. Looking at Cinebench 2003, prime95, and a few other benches, I get somewhere between 300x and 850x faster for the modern CPU over the Pentium 3.
For me, the biggest change in performance in my life was going from spinning disks to SSDs. That change felt bigger than any other leap by a long shot.
This was the most impactful upgrade/breakthrough for me. The first time I put even a SATA SSD in my PC at home I was completely blown away. It still blows my mind somewhat the amount of compute I have sitting on my desk though, both in terms of memory and CPU/GPU power, but that move from spinning rust to solid state was huge.
Then Apple did to me again with the M1 launch and NVMe speeds that made swapping nearly imperceptible.
akshually, it's also more closer to 500-1,000x. You can't look at clock speed only. Processor architecture makes all the difference. Pipelining, SIMD, memory bandwidth, blablala, everything got way better. Better approximation would be to use something like a synthetic benchmark or just (theoretical) FLOPS of each.
Otherwise, we can say that 6502 at 15Ghz is better than what you have now: https://news.ycombinator.com/item?id=22859706