SLI vs single card

[slick2004]

How much more performance do you get playing games??

 

[BlueAcolyte]

Anywhere from nothing to almost 100% scaling. Generally I think it's 20-50% faster than a single card, but it really depends on if the application can take advantage of SLi.

 

[Billb2]

..and the rest of your system

 

[JPB]

I agree with Billb2. Before anything can really be recommended, it is important to know what the rest of your system specs is.

However, in my opinion....I would stay with a single card.

 

[Hugh H]

Well, my experience so far has been semi-positive. First, that SLI bridge can be a PITA sometimes and I broke it once trying to remove it. (Forget regular bridges, Asus long flexible bridges FTW!)

Second, SLI is not just plug in two cards and play!!! You have to have the best SLI drivers (forums search), and you sometimes need to setup each individual game profile on the Nvidia control panel to take advantage of a specific SLI mode (AFR 1, AFR 2, Nvidia reccomended, etc...).

Minimum framerates are pretty low, altough they should usually be a couple of FPS more than with 1 card regardless. (for example, my minimum FPS with 1 card in World in conflict was 9 FPS, with 2 cards it was 11 FPS)

I have had no experience with microstuttering whatsoever (I've tried looking for it, but to no avail). I am sure if I run some benchmarks that detect this stuff I would find out about it. Otherwise, my gameplay experience is smooth.

2 or more cards generate more heat, and require more power. You have to make sure your PSU is up to the task.

If you are willing to deal with these issues, then SLI does bring a significant performance increase in my experience.

My Examples (1900 x 1200 resolution)

(Everything as high as it goes, including AA and AF)
Worl in Conflict 1 card: 19 FPS
World in Conflict 2 cards: 34 FPS

(All settings on high, no AA)
Crysis 1 card: 25 - 29 FPS
Crysis 2 cards: 42 - 46 FPS

I've also noticed it working on Call of Duty 4 and Team Fortress 2 but it's a little bit of overkill on those games.

So to summarize, it is no magic bullet, but it does work. I haven't encountered a single game that does not uses it. (I've read that Age of Conan does not scales with any multi-GPU setup, not sure if this has changed.)

My next GPU setup? A single powerful card (hopefully the successor to the 280 gtx)