SST-96 is basically a Voodoo Graphics which works together with an on-board 2D chip. This way you don't need a seperate 2D videocard for normal display.
Most cards featured an Alliance Semiconductor AT25 chip but some cards had a Macronix chip.
The Voodoo Rush didn't perform as good as the Voodoo Graphics because it had to share memory bandwidth with the 2D-chip. Compatibility was also less than the Voodoo Graphics (driver-wise, support for games and support in conjunction with motherboards).