Ask LH: Is It Worth Running Two Graphics Cards In My Gaming PC?

Dear Lifehacker, I'm building a new gaming PC using your guide, but I have one question: Is running two graphics cards worth it? Some people tell me I can get more bang for my buck with two midrange cards, but others say I should get one high-end card instead. Which is true? Thanks, Dual Card Dude

Photo by Gregg Tavares

Dear Dual,

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). With 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 the 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 less. 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 grunty as possible.

So that sounds awesome, right? Unfortunately, running multiple cards comes with some downsides. 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.

Cheers Lifehacker

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Comments

    Disagree with 'phishy''s advice. When your single card starts to struggle with modern games, upgrade to a single current generation card. Budget to upgrade the graphics card every 2-ish years and you should have no problem. SLI/Crossfire is an enthusiast option that brings a whole extra level of pitfalls and processing power sacrifices, not a filler for bridging card generations.

    The rule of thumb is this: for the same performance or expenditure (or both), a single card is always a better choice than a multi-card setup. If you're more worried about price than raw performance, buy one generation behind the current, there's always a steep price drop when a new generation comes out.

      Here here - in the past I've always made incredibly expensive gaming machines, but now I use my work laptop for all my gaming.

      Why? Because I have it on me, wherever I go. And I get a new one every few years, and with the hardware-lag from consoles, most* games generally don't spend more on graphics that consoles can't use.

      *There are some exceptions, but not as much as I would like.

      Plus you need a massive freaking case in order to fit two cards. They're only getting bigger and bigger it seems.

      Plus the person who has bought a 560Ti has probably skimped on CPU. SLi and CrossfireX require a decent CPU with a healthy OC to get the most out of the dual card setup.

    Probably worth noting that any savings made on SLI/Crossfire might be swallowed up having to buy a motherboard with 2 16x PCIe slots rather than just 1. A lot of mid-range motherboards are perfectly fine spec wise, but only tend to give you 1 16x PCIe.

    As a multi-monitor gamer, I've been running SLI and Crossfire combos for a a long time now, and just want to say a few things about the cons listed:

    More power, heat & noise - this is true, but current gen cards use significantly less power and make less noise than previous generations. a GTX 680 will draw on average about 175 watts compared to the GTX 580 which averaged 245 watts. Heat is always a concern, so a case with good ventilation is needed. I'm currently using a Cooler Master Silencio 650 which offers good sound reduction without sacrificing too much ventilation - a good compromise case.

    SLI & crossfire support for games - not so much of an issue any more, most major release games will support it out of the box and AMD and Nvidia do a good job of updating their drivers regularly to address issues. The latest beta of Nvidia's Geforce Experience tool now supports SLI as well, which makes optimising supported games very easy.

    Micro stuttering - still noticeable in some games, and probably the one area that still needs a bit of work - It's not so much a choppiness in games, more of a flickering of some textures. Both vendors are doing a lot of work on this and Nvidia recently released FCAT (frame capture analysis tool) to help users identify issues.

    The bottom line - a single card solution still means less issues, but SLI gaming has improved a lot recently and with focus it's now getting from the vendors, will continue to improve.

    Its all about resolution. If you are just running one 24inch monitor at 1920x1080 then one 670 GTX for example would be fine. However if you want to have 3 24inch monitors at 5760x1080 spanned with Nvida surround then two 670 GTXs would be required.
    Through my research I determined two 670 GTXs would give me the bang for the buck for running battlefield 3 over three screens. Oh and does it look awesome =).

      Yep, do have to agree. Its all in the utilisation. I saw this very setup with BF3 around a year back and was blown away by it. Stunning. Absolutely Stunning. I was told because it was primarily for vehicles and aircraft he wanted to get a THIRD card and see if he could do a two monitors over his shoulders so he could 'look behind him'. Dunno if that was possible at all but it sure would be interesting to see if it was possible.

    I've just been through the graphics card upgrade dance over the last 9 months, going from SLI Nvidia 7950's, to a GTX550ti, (then a full CPU/MB/RAM/PSU upgrade), to a GTX560ti, and now a GTX650ti. In each case I've sold off the old one ($50 for the 550, $100 for the 560 and picked up the 650 for $200), so I haven't been much out of pocket with each step, and can now play MWO at 60FPS, or record at 40FPS.

    However, looking at taking the next step according to the benchmarks the next cards up don't seem to actually offer that much of an improvement for the price, so it really does seem like I would just be better off picking up a 2nd 650ti in a few months for what should be under $150...

    When I put together my new PC, I reused my old 560 Ti and bought another one to SLI them - spent only a small amount of money to get a decent performance boost.

    However, when I first started using the new setup (over a year ago now), SLI had major problems. Some games went from working fine to crashing if SLI was enabled.
    Others would reboot the PC when they crashed. No blue screen, Windows thought I improperly shutdown - just playing fine one moment and BIOS POST the next.

    These days it's been a while since that's happened, but there are still some games that just don't like running in SLI mode - Battlefield 3 usually crashes about 1 minute in with SLI enabled.
    Other games run fine in SLI for hours at a time.

    So consider that when considering multi-GPU setups - a single card will probably cause less headaches, annoyances and crashes than multiple cards.

    But when it does work, it works well!

    I've always run dual monitors, so I've been doing double duty cards since DirectFX days. Now I've got 2x30" monitors, so the 7970 was my solution. Wanting to crank up CRysis3, so now getting a 3rd 7970 looks to be in the cards. Sad thing is it's now 1/2 price!

    Idiotic thing is that the whole point of DirectX was supposedly to bring out a unified interface between hardware and the software API, so that optimizations only needed to come from the driver side; all tha t software would see is a "video output."

    Sadly that's not the case and we find that some games are developed for ATI and others for nVIDIA. Sigh!

    Look at benchmarks on H[o]CP and you see the glarign disparity.

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