Using two (or more) video cards in tandem—known as “SLI” for NVIDIA cards and “Crossfire” for AMD cards—can get you better performance, sometimes even for less money than you’d spend on a comparable single card solution. However, whether it’s worth it is another story. Here’s what you need to know.
How SLI and Crossfire Work
To run SLI or Crossfire on your system, you need a few things: a compatible motherboard, two compatible video cards, and a “bridge” that connects the two cards together (these usually come with your motherboard or video cards). In SLI, you need two cards that have the same GPU—for example, two GTX 560 Tis. They don’t have to be from the same manufacturer, they just have to both be GTX 560 Tis. Crossfire has a bit more wiggle room, allowing you to pair some GPUs with other similar cards—like a Radeon 7950 with a Radeon 7970. To see which cards are compatible with one another, check out NVIDIA’s SLI page and AMD’s Crossfire page. Tom’s Hardware also has a great FAQ if you’re interested in finding out more.
Once you install both cards and the necessary bridge, you can open up your driver’s control panel and enable SLI or Crossfire. Make sure your drivers are up to date and play a game—if your drivers support SLI or Crossfire for that game, you’ll notice a significant performance boost. It won’t be exactly twice the performance, and every game will be a little different, but in many games you should find that everything runs more smoothly—with some exceptions.
The Pros and Cons of Multiple Video Cards
So why would you run multiple video cards? The main reason people go for it is its price to performance ratio. It varies from card to card, but in some cases, running two mid-range cards is slightly cheaper than running one comparable high-end card. You can get the same performance for a few bucks cheaper. They’re also ideal for multi-monitor or high-resolution gaming. Plus, they look sweet, and some people just want to make their rig look as baller as possible.
So that sounds awesome, right? Unfortunately, running multiple cards comes with some cons. For example:
- Two video cards sitting closely together in your case will draw more power, produce more heat, and produce more noise. If you’re concerned about any of those things, SLI and Crossfire may not be for you.
- Not all games support SLI and Crossfire. This depends on your video driver, not the game itself. NVIDIA and AMD often update their drivers to include multi-GPU support for new games, but if one of your games isn’t supported, you’ll either have to deal with one GPU or tinker with your driver settings to get the game working yourself.
- SLI and Crossfire can sometimes cause a phenomenon called micro stuttering that makes the video look a tad choppy. It can be particularly aggravating to some people, especially at lower framerates.
In short, using two video cards may require more attention and tweaking on your part, whether to compatibility issues, heat, or just dealing with micro stutter.
So Is It Worth It?
We can’t tell you what will work for you, but I almost always try to go with a powerful single card rather than two cards in SLI or Crossfire. To me, it’s worth the extra $50 (or whatever it is) to have a card that works without system tweaks, without the extra noise, and without the chance of any micro stutter issues.
However, there is another school of thought, that says you can buy a good card now, and SLI it later. Tom’s Hardware user phishy714 explains:
With a [single GTX 560 Ti], You will be playing new games on high settings with pretty good fps easily for the next year. . . Once you start noticing you CAN’T play them on high settings, that’s when you buy another GTX 560 Ti (which will be dirt cheap by then, probably around the $120 range) and SLI them. Your system will then easily do another year’s worth of games on HIGH settings.
After that, when your GPU is two generations old, that’s when you scrap them both and get a new card.
This still means you’ll have to deal with the cons of SLI, but it allows you to wait a little bit longer before dropping wads of cash on a brand new card—you can buy an older card for cheap and eke more performance out. Of course, you could always just sell your old card on eBay and buy another single, high-end GPU too, which will save you the trouble of SLI and Crossfire.
In the end, it’s all about how much work you want to do. Some dual-GPU configurations may not require any work, but it’s hard to know that out of the gate—you always run the risk of having more work when you get multiple cards. But in some cases, it may be worth the trouble.
