The GeForce 3 was Nvidia's third-generation GeForce chip, and comprised of three chips - the GeForce 3, the GeForce 3 Ti500 and the GeForce 3 Ti200.
The first GeForce 3 chips was released in March 2001, three months after Nvidia bought out the near-defunct 3dfx. It differed from the GeForce 2 in three main areas - the first was the addition of Vertex and Pixel shaders - specialised units (required under the DirectX 8.0 specification) designed to execute small Transform and Lighting programs, thus freeing up the main T&L units for larger operations. The second was Lightspeed Memory Architecture (LMA), which was designed to exclude overdrawn (objects obscured from view) objects from processing, and also managed the memory bus better than in the GeForce 2 chips. The third was the changing of anti-aliasing from Super-Sampling to Multi-Sampling, which was more efficient.
In terms of performance, it sometimes lost to the GeForce2 Ultra (which was clocked higher - 250 Core/460 Memory vs 200 Core/460 Memory on GeForce 3), but largely outperformed the GeForce 2, Radeon and Voodoo 5 cards (it probably would have outperformed the Voodoo 5 6000, but this is moot since the V5 6K was never released), especially when Anti-Aliasing was enabled.
The second revisions, the GeForce 3 Ti500 and Ti200 were released in October 2001, at around the same time as ATI's Radeon 8500. The Ti500 had higher core and memory clocks (250 Core/500 Memory), and was designed to outperform the Radeon 8500 (which it did). The Ti200 was a cheaper chip, designed to fill a niche occupied by the lower-priced Radeon 8500LE (some say that the Ti500's yields were unexpectedly poor, and the Ti200 was a way of making up the cost of making the chips, though this has never been confirmed) and clocked lower than the GeForce 3 (175 Core/400 Memory). The Ti200 proved popular with enthusiasts, as it could be run at GeForce 3 speeds (and Ti500 speeds in some cases).
Despite having performance supremecy throughout it's lifetime, the GeForce 3 series never had a mainstream card (the Ti200 was released relatively late in the chip's life, and in spite of being priced lower was never really a mainstream solution) and was to date (December 2003) the least successful of the GeForce series in sales.