Though, the late 90s feels achievable. The Front Side Bus of the Pentium III maxed out at 133 MHz, single transfer (and was often configured at 100 MHz for low

Though, the late 90s feels achievable. The Front Side Bus of the Pentium III maxed out at 133 MHz, single transfer (and was often configured at 100 MHz for lower spec CPUs), and the AMD K6 was even slower. I don't have much PCB design experience, but my understanding is that 133MHz is quite achievable for hobbyists these days. Things very quickly go off the rails after that.