AMD has been really solid. I’ve built a number of PC’s and there’s I’ve never run into an issue with the CPU’s. the R5 2600, 3600, and R7 5800 and 5800x are all surprisingly efficient chips out of the box, but I played around with each and found even crazier undervolt settings. My server PC draws practically nothing except if there’s something using the (NVIDIA) GPU extensively (and even then it’s like, oh no, is it almost 75 watts? better call the fire brigade! lmao).
And obviously the R7 5800x is just a monster, although I’ve consistently seen that it runs hot but… I air cool mine and it’s never really going above 85c when under full load on stock, and if you play with undervolting at all it’s pretty easy to keep the exact same performance while lowering the total power delivered. Although I’ve found that it goes up to 85c still and the chip just runs faster…