|
|||||||||
 |
XFX 7800GTX SLI Video Card Review :: Features
My first video card was TNT with 7 million transistors. That was a mere 7 years ago in 1998. Computer graphics cards have become ever more complex with the 7800GTX having over 302 million transistors. To put this number in perspective, that's more transistors than Intel's Pentium 670 and AMD's FX-57 CPUs (the fastest single-core CPUs on the market) combined. I only mention this because in the CPU space transistor numbers have doubled every 18 months. Video cards have increased transistor counts every 18 months as well. NVIDIA decided to improve the pixel shader pipeline in the 7800GTX cards. NVIDIA included 24 pixel shader pipelines on the 7800GTX, an increase of 50% over the 6800 Ultra that was NVIDIA's previous high-end flagship card. Further, they improved each pixel pipeline to increase performance in the most commonly used shader operation MADD (multiply add). The G70 is capable of nearly twice the shader performance as the NV4x architecture. G70 has 8 vertex shader pipelines. This is an increase of vertex shaders of 2 over the GEFORCE 6800 series of cards. G70 is capable of outputting two vertices a clock, giving the XFX 7800GTX a total theoretical output of 900 million vertices a second. The G70 can do vertex texturing, allowing for effects like displacement mapping, geometry instancing and full support for Microsoft's DirectX 9.0c Vertex Shader 3.0. NVIDIA says they redesigned the vertex shader from NV4x to G70 to reduce the time to set up and perform geometry processing. Intellisample 4.0 is NVIDIA's latest trademark for their image improving technologies. The GEFORCE 7800GTX has the ability to run 4X rotated grid multisample antialiasing in a single cycle, same as the GEFORCE 6800 Ultra. NVIDIA introduced two new modes of AA with the 7800GTX, Transparency adaptive supersampling and Transparency Adaptive Multi Sample AA. TSAA allows for antialiasing to be performed on thin objects like a chain-link fence or vegetation. High Dynamic Range lighting can dramatically improve lighting in a game or application. One of the underlying facts of video cards today is they generate 32-bit color 8 bits for red 8 bits for green 8 bits for blue and 8 bits for the alpha channel. One problem is this only represents a range of 256 to 1 maximum. The human eye can differentiate between light level differences on a range of over 1000 to 1 and the maximum number of possible colors is 10 to the 12th power to 1. The GEFORCE 6800 Ultra and 7800Ultra has the ability to use 16-bit per color component rendering, giving a range of 65,536 to 1. Discuss This Article
|
|
|||||||
