Only a couple of my work machines use DDR4. Most of my own kit, both for work and for play, uses DDR3 which is cheap and plentiful.

I avoid dedicated GPUs which have always been a money-pit. I find modern video games dull and boring, and this is not offset by them being very very pretty. Gaming for me peaked with Quake II and there's been nothing of real interest since Portal and Untitled Goose Game.