Graphic effects: What Is Anisotropic Filtering?
Anisotropic filtering (AF) is a graphic algorithm of improving the surface texture of an object. Where anti-aliasing is a method of making the edges of an object smoother, the anisotropic filtering is a method of enhancing the way how the objects looks inside, it concerns to all spaces between the edges. Every 3D objects that are used to build a game environment are textured. Texture is no more than a “coat of paint” that covers all those flat polygons to make them look like skin, wood, metal or bricks in the wall. Anisotropic filtering is a technology that became an standard effect in graphics cards in the early 90’s. Now the anisotropic filtering is widely used in graphics hardware.
Types of anisotropic filtering(AF)
There are three types of anisotropic filtering (AF). We can differentiate three methods of AF - bi-linear, tri-linear and full anisotropic. The anisotropic filtering is very powerful method, but it also uses lots of GPU performance. Settings that are available for anisotropic filtering are from 2x to 16x. When the level of anisotropic filtering is higher it provides more clear and sharp texture details, but it effects with more GPU usage. Modern nVidia graphic card such as Geforce 285 or even older models like Geforce 8800 handles 16x anizotropic filtering in resolution 1280 x 900 with no problem. For Geforce 285 even 1680 x 1050 is not a challenge, that because of use higher-quality AF algorithm. You can feel the difference between Anizotropic Filtering ON and OFF. Just take a look how anizotropic filtering looks like in action. These examples are a screenshots from 3DMark06 - the graphic benchmark tool. You can open those examples in a new window or tab, switching between them you can see the true difference.
3DMark06 Anisotropic Filtering (AF) OFF:
3DMark06 Anisotropic Filtering (AF) ON:
In short, anisotropic filtering is used when the generated textures are away from the viewer. It gives a smoother border between High resolution textures close to the viewer and lower resolution textures which are used away from “your eyes”. It is very useful for the textures in games with the far horizon. Of Course the textures resolution decreases looking further.
Anisotropic filtering vs. graphic cards performance
Anisotropic filtering can have an effect on games performance, even more when it’s used together with Anti Aliasing (AA). Companies building graphic cards such as nVidia are developing this filtering method to gain the best performance. To speed up AF, Nvidia specialists have initiated a special algorithms that makes Anizotropic Filtering calculations faster. Unfortunately it effects the lower amount of AF varies depending on the angle of the surface. The newest cards from nVidia use a higher-quality AF algorithm that have no problem with it but it results in a more round pattern.
Graphic effects: What is Anti-Aliasing?
Full Screen Anti-Aliasing (FSAA) or simply Antialiasing (AA) is a method which reduces the effects of aliasing. You wonder what the Aliasing is? It is simply the jaggedness and pixelation of computer images. It is particularly seeable on things like the straight edges of objects, or the outline of walls or ground in 3D games. These sharp jagged edges can even produce a “sparkle” effect somewhat when you are moving around in a 3D environment. When AA is enabled, it uses your graphics card’s hardware to blend the edges of the jagged lines and hence produce a smoother image.
Anti-Aliasing can have a different multiplicators, usually in steps of 2x, 4x, 6x and 8x. If it’s used the higher is the level of Antialiasing, the image is dynamically smoothed, but it laso uses much more graphics card resource. GPU need more strain processors to recalculate the graphic to produce these smoother images. Also, the higher the level of AA the greater the blurriness you can see. It is sometime a disadvantage because you game or image could become too “cartoon smooth” in appearance, which is not always the ideal effect.
What is the nVidia SLI?
SLI means Scalable Link Interface and it is a brand name for a multi-GPU solution used by Nvidia for linking multiple video cards together to generate only one output. SLI is an system of parallel processing for graphics, designed to increase the multi-processing power available for graphics.
Sli system wasn’t designed by nVidia engeneers. The name SLI was first used by company called 3dfx - former leader in graphic cards, it was famous for creating the very effective graphic accelerator , based on chip called “Voodoo”. Voodoo was ruleing all over the world. I remember my first diamond monster graphic card with voodoo chipset - it was world first graphic card that was an appard module to primary graphic card, it was called graphic accelerator,. It’s performance for those days was magnificent. It was the beggining af this technology. 3dfx relesed it under the full name Scan-Line Interleave, which was introduced to the consumer market in 1998 and used in the Voodoo2 line of video cards. After buying out 3dfx, Nvidia acquired the technology but did not use it. Nvidia company re-released the SLI name in 2004 and intended for it to be used in modern computer systems based on the PCI Express (PCIe) bus - whitch is actual fastest graphic interface. However, the technology behind the name SLI has changed dramatically. That’s how looks the double Geforce 9800 gt cards connected with nVidia SLI system:
Soon I’ll write about SLi performance and I’ll try to answer the question: Do she SLI really doubles performance with two card connected? Is it worth to buy single better more expensive card or two weaker cards set in SLI mode?
Overclocking Gainward 9800 GT
Gainward was always the leading nVidia partner who adds something special to its GeForce Versions. Gainward graphic cards everytime was quite easy to overclock. To improove your core clock all you need to do is install special Gainward’s Expert Tool on your computer. You can find it on official gainward site or you can simply download it by clicking here: Gainward’s Expert Tool v. 7.0.
After installing this small program you’re albe to set your card for better performance. The standard rates for Gainward 9800GT are:
- 600 MHz for Core Clock Setting
- 900MHz for Memory Clock Setting
- 1500MHz for Shader Clock Setting
You can change your clock setting by simply moving the rates. The maximum values you can set using Gainward Expert Tool are:
- 700 MHz for Core Clock Setting
- 1000MHz for Memory Clock Setting
- 1760MHz for Shader Clock Setting
Remember to have the Link clocks checkbox on. Expert tool will evenly distribute the power through the all three rates.It’s important to make a test after changing your graphic clock. Warning! You have to watch out for overheating of you Nvidia processor and memory. If you don’t have any additional cooling fan , you should use your Expert Tool to manage the fan speed on your GPU.
You have to watch out for the temperature of your GPU. It’s important to try keep temperarure not higher than 55/57 degree. The best solution is to set your fixed fan speed to the maximum and check from time to time the GPU thermometer vaule. If your temperature will be to high (especially in passive cooling models) try to decrease all the clock values. And that’s all. It wasn’t so difficult, right? Have a nice fun! Stay tuned for next articles:)