I don't even know what his build ran at in total, but he had $1700 (x2!) USB repeaters using fiber optic to directly connect USB peripherals all through his house, half a terabyte of ram and 4 GPUS. I think you could build a lesser machine to cover most household computing needs.

I don't think the core speed would matter much - Steam reports 37% of gamers are using 3ghz-and-below processors so they may be mediocre but still competent:

https://store.steampowered.com/hwsurvey/processormfg/