SiS (Silicon Integrated Systems) are better known for their system chip solutions rather than anything else. SiS had previously dabbled in the video arena but with little success. When I say little, I do mean enthusiasm, after all, the SiS 6326 video processor was the most used "Value" card in OEM systems for some time.
As mentioned above, SiS started in the 3D arena with integrated video on their Socket 7 chipset line, making them one of, if not, the first vendors to produce video on a chipset, better known these days as onboard video. This video controller was the integrated version of the 6326 video controller.
SiS later moved this controller into the value market by producing the chip itself for PCI and AGP operations. With support for up to 8MB of onboard SDRAM this card was rather used up by the OEM market for cheap PC's. Unfortunately, even for the value users, the card was a total failure. Compared to S3 Savage 3D and even S3 Virge, this cards 3D performance was well below playable levels.
SiS didn't go put their feat into the water until the 300 and 305 chipsets were released. This was SiS's first real attempt at the 3D market. The 305 graphics chip allowed full AGP2x support, 128bit 2D/3D Engine and 64bit memory pipeline on the 300 (128bit on 305) did result in a increase in performance, but still not enough to compete against nVidia, who had the TNT2 out at the same time.
SiS's last 3D chipset was the 315 which was an actual GPU (Graphics Processing Unit). This was a major step towards the goals of SiS for a fair priced, good performing video card. 315 supported AGP4x transfer modes, 256bit engine and 128bit SDR or DDR memory. Unfortunately though, cards based on this chipset were known for shorting out Intel 850 and 845 motherboards due to incompatible voltage issues.
SiS has taken a long hard look at their goals as well as what the market really want and have now come up with what is being called "The next big thing" - Introducing the SiS Xabre GPU.