Xorg with a compositor does the exact same thing with full backing buffers for every window. The only way X is using less RAM is if you run without compositing.

Xorg with a compositor does the exact same thing with full backing buffers for every window. The only way X is using less RAM is if you run without compositing. If you're not using a compositor, you must be either living in the 90s or using a device without a supported GPU. Compositing is not new, people were excited about Compiz desktop cubes and wobbly windows back in the mid-2000s! A Wayland compositor running directly on EGL should always be faster than Xorg with a compositor. Xorg acts as an awkward middleman between your app and the compositor, wasting time on buffer copies.