I have.
1 threadripper 3 vegas
1 ryzen 2700. a 1080ti
1 ryzen 3700. a 1660
1 ryzen 3800. a. 1660
4 ryzen 3900. all have a 1660
these rigs burn 7.20 at 10 cent power
they earn 13.20 so makes 6 dollars a day or 2000 a year i had to buy the 3000 series cpus. got some sales
cost was 2500 for the six cpus. under 600 for some mobos.
I sold older amd cpus. got 300
purchased some ram. cost 240.
sold a pair of simple miner intel rigs for 1000.
so maybe 3400 spent to upgrade minus 1240 is 2160
In theory I could have it all paid by Jan 2021.
notice no rx 590 no rx 580 no rx 570
i do have amd vegas and gtx 1660 along with the gtx 1080ti.
pretty happy i did the upgrades.
I have 4 3900x rigs myself nice rigs for dual mining CPU and GPU but if i had to do it again i'd by the 3x threadripper 32 cores vs 12 basical 3 in 1