This enforces a path where window contents often round-trip through the X server before composition. Quantitatively, this typically adds at least one frame of input lag compared to the zero-copy direct scanout path available to monolithic wayland compositors. You likely won't notice this while editing text. However, the architecture doesn't perform well when you attach an external monitor. Since X11 shares a single virtual coordinate space, it cannot synchronize VBLANK across two outputs with different refresh rates or clock domains.

ps: and please don't call your 2018 machine vintage, it makes my secondary thinkpads feel prehistoric :D

To my eye most Linux de’s are much lighter or responsive than windows or Mac