that's only 133-times as much CPU power

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