Alienware reacts on the recent presentation of NVIDIA's new SLI solution and explains the similarities and differences of both technologies.

It was a big surprise when Alienware announced their Video Array technology at E3 Expo in Los Angeles last month. But an even bigger surprise was NVIDIA's announcement of its new SLI technology yesterday.

The dual graphics card solutions from both Alienware and NVIDIA are quite similar. However, Alienware's Video Array has some advantages. For instance,it works with video cards from NVIDIA, ATI and any other video card manufacturer. This is made possible by the Video Merger Hub (VMH). The display output from both video cards is connected to this device, where they are merged together for final output.
At E3, Alienware's demo system ran with a fixed split ratio of 50/50, so both cards always rendered 50% of the screen. A load balancing technology is currently under development. This makes sure that both cards are fed with the same graphics load to maximize the performance.

Alienware updated their Video Array FAQ to show the similarities and differences to NVIDIA's SLI:

Similarities:

• Goal
• 1. Both technologies have the same objective; to dramatically increase the graphics performance of your PC by using multiple graphics cards working together to draw the same image

• Performance
  1. The performance increase resulting from either technology could be up to 100%. These gains will be realized in applications that are primarily limited by the GPU. For example, rendering software, CAD/CAM programs, and the latest games like Far Cry, Half-Life 2, and Doom 3.
  2. Both technologies require extra overhead (e.g. textures have to be sent to both video cards). Therefore, some data travels twice through the PCI Express bus and, as a result, the average performance increase could be less than 100%.

Differences:

• Flexibility
  1. Alienware's Video Array works with video cards from any manufacturer; ATI, NVidia, 3DLabs, Matrox, or others. Since you are not tied to any one manufacturer's products, you can configure the Video Array with the video cards that work best for your application.
  2. The Video Array uses off-the-shelf video cards and drivers. There is no need to have any special provisions in hardware or software for Video Array to work. When there is a new feature or optimization implemented in the drivers, they become readily available through Video Array.
  3. Alienware's Video Array is not limited to 2 video cards. Future implementations may take advantage of this and put 4 or more video cards into one system. This would probably be more geared towards professional applications like rendering farms.

• Full Solution
  1. It's not enough just to get two high-performance video cards to work in parallel. The combined power requirement and increased heat generated by two graphics cards are beyond the capabilities of most PCs on the market today. As a result, Alienware has engineered complete power and liquid cooling systems for Video Array and will be bringing the total system solution to market in the ALX line of high-performance PCs.

• Features
  1. Video Array implements Frame Locking with any video cards, a feat previously available exclusively on extremely high-end professional class video cards. Frame locking synchronizes display refresh and buffer swaps across multiple cards, preventing visual artifacts and ensuring image continuity in multi-monitor (or multiple video card) applications like simulations

In a press release (see link below), Alienware's Frank Azor explained that NVIDIA's SLI might be an option for future Alienware PC's, but the development of Video Array continues and focuses on cards from ATI, 3D Labs, Matrox and others.

More information on Video Array and SLI:

Alienware's Graphics Array Adds to Gaming Wallop with a Double Graphics Card Punch
NVIDIA Takes a Walk on the SLI Side with Double Graphics Processing
Alienware's Graphics Array FAQ
Tom's Hardware US