What does anti-aliasing actually do to your PC games?
PC games offer multiple anti-aliasing methods that smooth jagged edges in different ways, each with its own trade-off between image quality and GPU performance.
Video games must represent curved and diagonal edges on a grid of square pixels, which creates stair-step patterns known as "jaggies." Anti-aliasing techniques smooth out these rough edges, but they do so through different methods, each with its own balance of visual quality and GPU demand.
Older, heavier methods
SSAA (supersampling anti-aliasing) takes the most straightforward but also most demanding approach, rendering the image at a higher resolution before downsampling it to the final output. It produces strong results but places a heavy load on the GPU, often reducing frame rates.
MSAA (multisample anti-aliasing) is less taxing, concentrating extra samples mainly around geometry edges rather than the whole image. More samples mean smoother edges but also greater GPU load. However, MSAA mainly addresses geometry edges, while aliasing from materials, textures and transparent surfaces can persist. Unreal Engine's documentation also notes that MSAA is supported only with the forward renderer, not the desktop deferred renderer, which is one reason common 2x, 4x and 8x MSAA modes aren't always available in newer titles.
Faster, newer methods
FXAA (fast approximate anti-aliasing) and SMAA (subpixel morphological anti-aliasing) work after the frame has already been rendered, detecting and smoothing high-contrast edges. FXAA is quick and low-cost but can soften image detail, while SMAA uses more advanced edge and pattern detection to preserve sharpness at a relatively low performance cost.
TAA (temporal anti-aliasing) draws on information from previous frames, helping reduce shimmering on fences, foliage or distant objects as the camera moves. However, when information from earlier frames doesn't align cleanly, TAA can cause softness or ghosting.
Newer technologies such as NVIDIA's DLAA, AMD's Native AA and Intel XeSS's Native Anti-Aliasing mode use deep learning while working at native resolution, and are positioned as quality enhancements rather than performance boosts.
