I've got an Intel i5 10600K, RTX 2060, 32GB of RAM, and an NVMe SSD. Running at 4K, but even so, my system performance isn't the issue.
Oddly enough, I just noticed that switching pages within the start menu animates at full rate. Everything else, like opening/closing the menu, right-click menu animations, etc, all run at a way lower rate. The rate stays the same regardless of settings—fullscreen/standard, 7/10/11 styles, different search engines, etc. all behave the same. It doesn't feel like lag. It's consistent, just consistently 20 FPS or so.