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NVIDIA GeForce 7 Phase 2 Review :: The New Cards
Common Features
The 7xxx series is a refresh of the 6xxx series cards. The 7900GTX and 7900GT both have the same number of pixel pipelines, ROPs (outputted Textures), and ALUs (Shader Units), (24, 16, 48) as the previous generation video cards, the 7800GTX. This should allow the 7900GTX to outperform the previous generation cards with the increased clock speeds of the card. The theoretical fill rate of the XFX 7900GTX is 10.2 Gigapixels a second and 15.3 Gigatexels a second.  Three Cards All NVIDIA cards since the launch of the 6800 Ultra in 2004 support Microsoft's DirectX 9.0c standard. The key features of this API include support for Pixel Shader 3.0 and Vertex Shader 3.0, support for floating point 32-bit color throughout the pipeline, FP16 blending, HDR (High Dynamic Range Rendering) and more. These are the key features of video cards released today. With the transition to Microsoft Vista later in the year, video cards will likely bring support to DirectX 10 features, but that's not currently an option. Pixel Shaders are small programs performed on pixels to give effects like shiny reflective armor, realistic looking water translucent skin, veins in eyeballs and more. Pixel Shader 3.0 is differentiated from PS 2.0 in longer pixel program lengths (65,536 versus 96), dynamic branching in the Pixel Shader, a backface register for two-sided lighting and more. F.E.A.R. uses Pixel Shaders in the water, in the smoke and fire effects. Age of Empires 3 uses Pixel Shaders in the cannon barrel, in the lighting and more. Vertex Shaders are small programs performed on vertices. Key differences between VS 2.0 and 3.0 include longer Shader program lengths (65,535 versus 256), Dynamic Branching, Geometry Instancing render to texture and more. Dynamic Branching speeds up performance by skipping animations and calculations on irrelevant vertices. Geometry Instancing allows the programmer to draw a object, uses several parameters to change the appearance of an object. For example, you can modify the color, the number of leaves, the number of branches on a tree being reused in a forest to differentiate it between another tree in that forest with Geometry Instancing. Natural lighting is one of the hardest things to do in a game. Part of the problem is the contrast between the brightest day and pitch darkness The normal computer monitor can display a contrast ratio of 255:1. The problem is the human eye can distinguish between thousands of variations in contrast. High Dynamic Range rendering allows the game designer to give natural colors to the games. HDR shows the difference between the lightest light and the darkest dark in a game that supports this feature. Transparency Anti-Aliasing helps cure artifacts that occur when transparent textures are not aliased. Examples of where TAA might help include: chain Link fences like those found in Half Life 2 and dense vegetation like that found in Far Cry. With normal AA, the insides of the fence links are a big mess. With TAA turned on, the mess is cleared up. PureVideo is NVIDIA's video technology similar in concept to ATI's AVIVO. The 7xxx series has a High Definition video processor and when used in combination of the PureVideo decoder has a lot of features and benefits including hardware decode acceleration, Spatial Temporal De-Interlacing, High Quality Scaling,Inverse Telecine, Bad Edit Crorection, Video Color Correction, Video Color Correction, LCD Sharpening and Integrated SD and HDTV Output. The Hardware Decode Acceleration accelerates videos such as H.264, Windows Media Videos, MPEG-2s and more. Spatial Temporal De-Interlacing sharpens the picture of interlaced displays. High Quality Scaling allows you to upscale or downscale an image while maintaining a clear picture. Inverse Telecine recovers original images from films-converted-to-video (e.g. DVDs, 1080i HD content), providing more accurate movie playback and superior picture quality Contents:
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