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XFX 512MB 7800GTX Video Card Review :: 7800GTX Features
When NVIDIA launched the 7800GTX card it seemed they had clocked the card very conservatively at 430MHz/1.2GHz core/memory. This gave the 7800GTX a fillrate of 6.8 Gigapixels and 10.32 Gigatexels a second with the 24 pixel pipelines and 16 outputted pixels a second. At the time, it seemed to be a good performance increase over the GeForce 6800 Ultra, which had similar clockspeeds, but only 16 pixel pipelines. The new card is designed with the same pixel pipelines and a clock speed increase of 120MHz for the reference card. The 512MB 7800GTX has a fillrate of 8.8Gigapixels a second and 13.2 Gigatexels a second, an increase of 30%. Memory bandwith is increased from 38.4 to 54.4GB/second a 42% increase. XFX chose to clock their card at 580MHz/1.73GHz, a 30MHz increase on both the core and memory clocks. Fillrate on the XFX card is 9.28 Gigapixels and 13.92 Gigatexels a second theoretical. Memory bandwidth is 55.36GB/second. The key features of the 7800GTX are support for Pixel and Vertex Shader 3.0, i.e. Shader Mode 3.0. NVIDIA cards have supported SM 3.0 since the release of the NV4x architecture last year. The 512MB version of the 7800GTX offers no new features when compared to the 7800GTX 256MB version. Also important to the 7800GTX is support for HDR and SLI. Pixel Shaders are small programs performed on pixels for special effects. Pixel Shaders can be used to simulate water effects, shiny armor refractions and reflections. Pixel Shader 3.0 allows for nearly unlimited shader lengths and dynamic branching. The 7800GTX was designed with more performance for the most commonly used Pixel Shader instructions MADD (Multiply Add) with up to twice the MADD power of the 6800 series. Vertex Shaders are small programs performed on vertices. Effects that can be done with the Vertex Shader include Procedural Geometry (cloth simulation, soap bubble), Advanced Vertex Blending for Skinning and Vertex Morphing, Texture Generation, facial expression, Particle System Rendering, lens effects, and displacement mapping. VS 3.0 allows for virtually unlimited shader lengths, dynamic branching and looping and more. NVIDIA introduced Transparency Antialiasing with the launch of the GeForce 7800GTX back in June of 2005. Antialiasing helps with jagged lines and the "stairstep" effect when a texture is thinner than a pixel. Transparent textures are not usually helped with normal Multisample AntiAliasing. NVIDIA's Transparency AA has two modes, Multisample and SuperSample. In SS, transparent textures are helped by Transparency AA. MultiSample Tranparency AA doesn't help as much in most situations.  No TAA  Multisample Transparency AA  SuperSample Transparent AA Before the advent of the floating point color, lighting variations in games was limited to 8-bit per component or a range of 255:1. The human eye can distinguish between ranges of about 10,000:1 and can distinguish between 10,000 colors at a given brightness. The GEFORCE 6800 was the first card to fully support Floating Point 16 blending and as a result, can do a range of 65,535:1. Games released including Far Cry and Half Life 2 Lost Coast support HDR lighting. With HDR enabled lighting is more natural, with beautiful reflections and realistic lighting from the sun. Here's a few pictures from Far Cry with HDR on/off and HL2 Lost Coast with HDR off, Blooming and Full HDR on.  Far Cry no HDR  Far Cry HDR On  HL2 Full HDR  HL2 Blooming  HL2 no HDR Contents:Discuss This Article
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