MSAA (multisample anti-aliasing): what 2×/4×/8× mean and why modern games dropped it

How multisampling works

With MSAA 4× the GPU keeps four depth and coverage samples per pixel. When a triangle edge crosses a pixel, the hardware records which of the four sample points are covered and blends the shaded colour accordingly: a pixel half covered gets 50 % of the edge colour. Interior pixels are shaded once, so the cost is mostly memory bandwidth and the resolve pass, not shader work.

The result is clean, stable edges without blur, which is why racing sims and flight simulators still offer MSAA: thin wires, car bodies and cockpit frames look crisp.

Why it disappeared from AAA games

MSAA only treats geometry edges. It does nothing for shader aliasing (specular shimmer), alpha-tested textures (foliage, fences) or ray-marched effects, which dominate modern scenes. Deferred rendering makes it worse: the G-buffer must store every sample, multiplying memory and bandwidth — MSAA 4× can cost 30–50 % of FPS in a deferred engine versus 10–20 % in a forward one.

TAA covers all those cases for 1–3 % of FPS, so engines switched. Unity URP and some mobile engines keep MSAA because forward rendering and tile-based GPUs handle it cheaply.

Settings advice

At 4K MSAA 2× is usually enough; at 1080p 4× is the sweet spot. Driver-forced MSAA for old games works only with forward-rendered titles.