CrossfireX | Quad SLi - Comparison

In this competitive world of gaming, graphic card manufacturer always comes up with newer technology to enhance the best experience in game. This post will cover about the technology provided by ATI Radeon and nVidia GeForce which is the CrossfireX by ATI and SLi by nVidia.

CrossfireX Technology
This technology enable user to have 4 graphic card on a motherboard. This graphic card need to be in the same family and for now only HD 3870 and HD 3850 support this technology. It means that you can have 2 HD 3870 and 2 HD 3850 on a motherboard.

CrossfireX is a Native Crossfire. The maximum resolution for Native crossfire is 2560x2048!! These are technique/modes used when rendering image:

• Scissor : Due to you can put different card on a motherboard (with limitation of the same family), there will be a faster video card and this will make rendering time is unbalance between graphic cards. To deal with this problem, Crossfire enable dynamic load balancing so the faster graphic card will render a bigger portion of image than the slower graphic card.
• SuperTiling: In this technique, the screen will be divided into several small portion (tiles) and each graphic card will handle the available tiles. Load balancing also being used in this technique.
• Alternate Frame Rendering : The first card render a frame. The second card render the next frame.
• Super AA : Increase image quality rather than performance.

Quad SLi Technology
For this technology, it doesn't use 4 graphic card but it use two GeForce 7950GX2 with 2 GPU on each card. In the Quad SLi technology, each card must have the same GPU but currently only GeForce 7950GX2 support the Quad SLi technology.

The maximum resolution for Quad SLi is 2560x1600.
The technique used:

• SFR (Split Frame Rendering), where each frame is divided in two and each half is sent to a different GPU to be processed. This is the mode used by SLI configurations using two video cards.
  
• Alternate Frame Rendering - Same as CrossfireX. The first card render a frame. The second card render the next frame.
• AFR of SFR. Here two GPUs process the first frame under SFR mode while the other two GPUs are processing the next frame also under SFR mode.
• SLI AA (Anti-Aliasing). This mode isn’t intended to improve gaming performance but increasing image quality. So far this mode does not work under Windows Vista.

Ok. Thats all from me, for now. Actually there are more information about those technologies but here I just give a summary of the technologies.

reference: http://www.hardwaresecrets.com/article/391