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IMPACT
IMPACT (sometimes spelled Impact) is a computer graphics architecture for Silicon Graphics computer workstations. IMPACT Graphics was developed in 1995 and was available as a high-end graphics option on workstations released during the mid-1990s. IMPACT graphics gives the workstation real-time 2D and 3D graphics rendering capability similar to that of even high-end PCs made well after IMPACT's introduction. IMPACT graphics systems consist of either one or two Geometry Engines and one or two Raster Engines in various configurations. IMPACT systems that included texture RAM (TRAM), such as the High Impact and Maximum Impact, also supported hardware-accelerated 3D texture mapping.
IMPACT graphics consists of five graphics subsystems: the Command Engine, Geometry Subsystem, Raster Engine, framebuffer and Display Subsystem. IMPACT Graphics can produce resolutions up to 1600 x 1200 pixels with 32-bit color and can also process unencoded NTSC and PAL analog television signals. Using custom Video Format Object (VFO) Files IMPACT graphics can also support resolutions of 1920x1080 (1080p) and 1920x1200 common in modern LCD monitors. IMPACT graphics systems' support for higher resolutions, refresh rates, and color depths are limited by their maximum pixel clock (160MHz) and limited video RAM.
IMPACT graphics subsystems come in three configurations for SGI Indigo2 IMPACT workstations: Solid IMPACT, High IMPACT, and Maximum IMPACT. The equivalent Octane Graphics Boards are referred to as SI (Solid Impact), SI+T (High Impact), and MXI (Maximum Impact). The Octane also introduced the SSI, which is a Maximum Impact system without TRAM. Later SGI Octane workstations used a similar configuration but with updated ASIC chips and are referred to as SE, SSE, and EMXI (E-series). IMPACT uses Rambus RDRAM for texture memory.
The IMPACT graphics architecture was superseded by SGI's VPro graphics architecture in 1997.
The three SGI Indigo2 IMPACT options, from least to most powerful, are: