Graphics and graphical processing take orders of magnitude longer than other fundamental machine instructions. It's just inherently slower than doing something

Graphics and graphical processing take orders of magnitude longer than other fundamental machine instructions. It's just inherently slower than doing something equivalent that requires zero graphical processing or monitoring of user input. It is common sense to anyone who knows the tech stack that underlies the pixels on the screen. This is no fault of Qt by any means. It's just the nature of the tech.