Intellisample is the brand name for NVIDIA's antialiasing method in GeForce graphics cards.
Version 4.0 is used in the GeForce 6 and GeForce 7 series, and includes two new methods, Transparency Supersampling (TSAA) and the faster but lower-quality Transparency Multisampling (TMAA). These methods are designed to improve antialiasing quality of scenes with partially-transparent textures (such as chain link fences) and textures at oblique angles to the viewing screen.
Intellisample 4.0 support was enabled, unannounced, for GeForce 6 Series cards in NVIDIA's display driver (Forceware), version 91.45[1]. This is not mentioned in the driver Release Notes or on NVIDIA's website.