How do you get Civ 6 to not take 10,000 years per turn late game?

[superchunk]

I've never had a game where the turn took a minute+ for CPU teams to complete on any Civ game and I've been playing them since Civ2. My current PC is something I built in 2015 and I never buy highest end. It has a i5-4690k cpu and GTX 960 gpu. While I'm not playing Civ6 all that much right now, my son has games quite frequently.