Difference between SLI and single cards solution ?

Question

Let's say I have two computers called A and B. I also have two 512MB VGA cards and a 1GB VGA card. All the three cards are from the same manufacturer and of the same model.

Now I connect the two 512MB cards in SLI mode to computer A. The 1GB card is connected to the computer B. Assume that all the other components (RAM, Processor etc) of the computers A and B are same.

1. Which machine will be the best gaming machine?
2. Which machine will be more expensive?

Explain your answers.

Answer 1

1. Since amount of RAM is not of the greatest importance, the SLI cards will win out. Remember in SLI you are not just doubling the RAM, you are getting a second GPU. This is assuming that all other things are the same on the 512 and 1GB cards. To be honest, the 1GB would only slightly outperform a single 512 card, but two SLI cards would beat it out.
2. The SLI solution would be more expensive, because simply doubling the amount of RAM on a card while keeping everything else the same will NEVER double the cost of a card, but of course buying two of them will
3. You didn't ask this, but I will mention it anyway. The most cost effective solution is to buy the best single card configuration you can. For example in almost all cases a single $500 card will outperform two $250 cards in SLI.

Answer 2

The 1GB VRAM graphics card will cost more than the 2 512 cards combined (this is taking for granted that you are buying cards worth buying). The SLI setup will dedicate one card to the vertical refresh rates, the other one to the horizontal refresh rates. The 1GB card will be used for both the vertical and horizontal refresh rates. Thus, it depends on what you want. For gaming, I would suggest the SLI setup. For graphics editing I would suggest the single card.

Answer 3

http://www.pcper.com/article.php?aid=175&type=expert
http://www.tomshardware.com/2006/06/05/geforce_7950_gx2/page2.html
http://www.amdzone.com/modules.php?op=modload&name=Sections&file=index&req=printpage&artid=95

SLI:

SLI is short for Scalable Link Interface. SLI is proprietary to Nvidia graphics cards and is a method of allowing two graphics cards of the same model to be linked and share the load of rendering the graphics on screen. Using two graphics cards linked via SLI greatly improves the performance of the system by rendering the graphics faster. Often up to a 2 times improvement is seen.

Single card solution:

Texas Instruments also is touting the interoperability of 13.56 MHz (medium frequency) systems and embracing the concept of a single solution card:
"Employee badges are moving beyond just access -- to single-card security systems that have to work harder to deliver a host of solutions from time & attendance to authorization to cashless transactions. The technology is ideal for large "campus" settings like corporate office parks, schools, health centers and hospitals, where single-card solutions connect employees, students or patients and staff with a range of networked security, authorization, information and transaction systems."


It sounds like a single-card solution is viable today in controlled environment settings, including self-contained campuses where one entity controls the functions for which the card can be used, and possibly in societies like China where central-planning still has a firm grasp. In North American and European culture, where there are so many free choices for so many different services, I think it will be a long time before we move to a single card solution in our everyday lives.