Introduction One of the traditional bottlenecks of 3D graphics hardware has been the rate at which pixels can be rendered into a frame buffer using conventional DRAM or VRAM. The 3D-RAM emerged from a complete rethinking of frame buffer technology and produces an order of magnitude increase in rendering performance. The factors responsible for the dramatic overall performance improvement include: • New Memory Architecture • 10-Mbits DRAM array supporting 1280 x 1024 x 8 frame buffer • Four independent, interleaved DRAM banks • 2048-bit SRAM Pixel Buffer as the cache between DRAM and ALU • Built-in tile-oriented memory addressing for rendering and scan line-oriented memory addressing for video refresh • 256-bit global bus connecting DRAM banks and Pixel Buffer • Flexible dual Video Buffer supporting 85-Hz CRT refresh • Write Mostly Interface • On-chip ALU • Four ROP units supporting 16 raster operations on byte data • Four Blend units blending the old pixel value with new information • On-chip hardware acceleration for all OpenGL blending modes(NEW) • On-chip hardware acceleration for all OpenGL stencil modes (NEW) • One 32-bit Match Comparator and one 32-bit Magnitude Comparator • Concurrent operations of DRAM, Pixel Buffer, ALU and Video Buffer • 32-bit synchronous high-bandwidth data bus interface with rendering controller • Blending operations in both (8, 8, 8, 8) and (4, 4, 4, 4) color modes (NEW) • One additional PASS_IN pin for flexible bit plane organization
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