The 64MB of 3.8ns DDR SDRAM runs on a vastly different memory controller than previous Geforce chips. The term memory controller is actually a misnomer because unlike the Geforce2 Ultra which uses a single 128-bit (DDR) controller, the Geforce3 makes use of four, interleaved, and load-balanced 32-bit (DDR) memory controllers culminating in a system that NVIDIA likes to call a Crossbar Memory Architecture. Both chips have 256-bits of bandwidth (Geforce2 Ultra: 128-bit DDR / Geforce3: 32-bit DDR times 4), but the Geforce3 is much more efficient. For example, when dealing with small sets of data 128-bit chunks for example the Geforce2 Ultra would using the entire 256-bits to transfer only 128-bits worth of data, whereas the Geforce3 can access the data in 32-bit chunks,
in parallel. This advancement is part of the Lightspeed Memory Architecture which also includes the Visibility Subsystem.
The Visibility Subsystem is very similar to ATIs HyperZ technology in that they both remove non-visible values from the z-buffer before they are sent to the frame buffer. This conserves memory bandwidth for pixels that are actually going to be seen on the screen. (The z-buffer is a part of the video memory that holds the depth values of onscreen elements by comparing these values, hidden pixels, as in, pixels that are blocked from view by other pixels, can be removed. The frame buffer is the part of the video memory that contains the rendered screens before they are displayed to the monitor). Like HyperZ, NVIDIAs solution also includes 4:1 lossless z-buffer compression which also conserves memory bandwidth.
But the major advancement that everyone should be (and is) talking about is the nFiniteFX Engine a key milestone in consumer-level, computer graphics. Made up of the Hardware Transform and Lighting Engine that we know all know (and love?) as well an nFiniteFX Pixel processor and an nFiniteFX Vertex processor. The Hardware T&L is no big news, but the chief innovation of the latter two is that they are programmable that is, game developers now have ability to program their own vertex and pixel algorithms.
If you remember Environment Mapped Bump Mapping (EMBM) which was introduced my Matrox, the nFiniteFX Engine has it beat. EMBM used bump textures to create the illusion of complex surfaces (such as water, rock, and human faces). This method has obvious limitations, not the least of which is the fact that this complex surface is fixed in nature i.e.: it is impossible for the objects texture to interact with the environment. With the nFiniteFX Engine, these surface complexities can be created and rendered in real-time, all at the developers whim, allowing a texture to interact with its environment. This opens up a whole new world of exploration for game developers to creates and game enthusiasts to enjoy.
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