Why does Windows feel more responsive than macOS?

I recently built a new gaming machine with Windows 10 and damn this thing is fast and responsive. When scrolling or simply moving windows around it feels like Windows is running at more FPS than macOS (for a lack of a better description).

I'm comparing this Windows machine to a 2017 5K iMac i5 7600K with SDD. I've been using it with High Sierra and recently installed Mojave. Based on pure specs the iMac has a 30% faster CPU, a similarish GPU, and the SSD is much faster. Both machines are running at 60Hz.

Also when doing benchmarks (geekbench, spedometer, etc) the iMac is indeed about 30% faster.

I know macOS used to have mouse lag which was fixed in El Capitan so I don't think this is it.

Firefox and Chrome feel a lot more snappy than even Safari on macOS. For example when switching tabs it feels instantaneous in Windows and in macOS it seems like there are a couple of frames of lag.

Any ideas what this is?