So, you've decided to join the true PC Gaming Master Race and get 3Dvision. Nice one! Once you've experienced the exquisite immersion that comes from gaming in proper 3D, you'll find it hard to ever go back. But 3Dvision comes with a performance cost, and you're wondering how your PC will handle it. How much 3Dvision affects your FPS varies game by game, but there are some rules of thumb.
Putting the Rules of Thumb to the test
In 3Dvision, the GPU needs to pump out twice the frames as in 2D (one for each eye). Based on this, 3Dvision users sometimes make two claims:
- Claim #1: Turning on 3Dvision in a game will generally halve the FPS
- Claim #2: 3Dvision and SLI are a match made in heaven, since the former requires two [similar] frames per eye, and the latter gives you two [similar] GPUs with which to render them.
Intuitively, these claims sound fair enough, but I decided to do some testing and find out for sure.
The testing system:
Asrock z87 Extreme9ac
core i7 4770k
Gigabyte GTX Titan x2 (SLI)
Windows 7 64-bit, Home Edition
Nvidia control panel settings:
I tested 8 games in four modes each:
- 2D single-GPU
- 2D SLI
- 3D single-GPU
- 3D SLI
- I used only games with built-in benchmarks, for accuracy.
- All games were tested at 1920x1080
- Unless otherwise stated, I used absolute max settings, including the crazy ones like SSAA
- In case any regular readers were wondering, my dedicated PhysX card was disabled for these tests
- I focused only on average framerates. I took note of maximum and minimum framerates too, but the story they told didn't deviate much from the one told by the average framerate results, so I left them out, for the sake of clarity
- I did between 3 and 5 passes for each test, depending on how satisfied I was that I was getting a trustworthy sampling (for example, Mafia II is notoriously variable, and therefore requires a larger test sample than Tomb Raider, which tends to give almost the exact same results each time)
- For the 2D tests, I disabled the 3Dvision driver completely (ie. I didn't merely press Ctrl-T)
How I present the results
- I first present each game's FPS graph.
- Then I collate the data from the FPS graph in two slightly different ways, and put those into a blue box and a green box.
- The blue box reveals how much of a benefit adding a second card (ie. SLI) made, both in a 2D scenario and a 3D scenario. This puts claim #2 to the test (is SLI really much more effective in 3D than it is in 2D?)
- The green box reveals how much of a performance drop I saw once 3Dvision was turned on. This puts claim #1 to the test (does 3D really halve the framerate compared to 2D?)
OK, lets jump right into the test results.
Not bad! Even though SLI brings a pretty dismal 18% improvement in 2D*, SLI scaling is much better in 3D - more than three times better, in fact. Claim #2 is looking pretty good.
Meanwhile, claim #1 seems pretty much on the money, unfortunately. Turning on 3Dvision in a single-GPU environment gives us a whopping 45% decrease in FPS. Not quite a halving of framerate, but close. It's better in SLI, of course, and an SLI user who switched to 3Dvision would only suffer a 26% decrease in FPS - from 78 to 57 - despite the fact that the GPUs would be still be rendering twice as many frames.
* As I showed in a previous article, SLI users may actually get a higher FPS in Batman Arkham Origins by disabling SLI and devoting their second card to PhysX.
I tested Tomb Raider with all settings set to max, except for SSAA, which was set to x2 rather than x4.
Unfortunately, Tomb Raider tells us a different story to Arkham Origins. While SLI scaling is beautiful in 2D, it's not as impressive in 3D (ironically, since it's again 59%). The single-GPU performance cost is again about 50%.
Here, we see not much difference between SLI and single-GPU. By the way, please note that I used the Helixmod fix for Bioshock Infinite for this test. I did not use Nvidia's "3D compatibility mode", which may have a different performance impact.
Ok, let's see some more charts.
OK, a fairly varied bunch of results there. Mafia II was reminiscent of Arkham Origins, with paltry SLI scaling in 2D but a handsome improvement in 3D. In fact, SLI scaling was better in 3D in every game except Tomb Raider. But only two games (Sleeping Dogs and Metro: Last Light) really did justice to the "SLI and 3Dvision are a match made in heaven" maxim of claim #2, with almost perfect SLI scaling in 3D (ie. almost a doubling of FPS).
Let's average it all out
OK, let's take the results of all 8 games, average them out, and see what we find:
Looking at the green box, we see that claim #1 is spot on: Switching to 3Dvision mode will tend to halve your framerate. This is mitigated somewhat with a second card, with 3Dvision's superior SLI usage narrowing the gap.
3Dvision's advantage in SLI is clear (47% vs 66%), though not as massive as claim #2 would have you believe. More to the point, it's somewhat unpredictable. Sometimes it vastly outshines 2D SLI (eg. Batman, Metro, Mafia II), while other times it has only a modest improvement (eg. Hitman, Bioshock). And in at least in one case (Tomb Raider), 3D SLI distinctly underperformed compared to its 2D counterpart.
One thing all 8 tests agree on though, is that when gaming in 3Dvision, SLI will always be significantly worth it. While 2D SLI gave only a 18% improvement in Arkham Origins, and 4% in Mafia II, 3D SLI scored at least 49% in every single test. A match made in heaven? Well, maybe not quite. But a good match, for sure.
So, is 3Dvision worth it?
Yes, yes, and yes. 3D makes games come alive like you've never seen them before. Objects become more lifelike, spaces become more cavernous, and the gameworld feels less cramped; hidden details emerge, and immersion goes through the roof.
However you choose to deal with the performance cost - whether by lowering graphical settings, forking out for stronger hardware, or just putting up with lower framerates - it will be worth it, as it'll still look better in 3D than it ever did in 2D.
And as these tests indicate, for those 3Dvision users considering an upgrade, SLI may not be a panacea, but it's still clearly a great bang-for-buck prospect.
Dave is a graphics professional and longtime PC power-user. He spends more on his gaming rig than a reasonable person should. He founded the indie game studio Volnaiskra, and is the creative force behind Spryke.