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The Importance of GPU over CPU in Stereoscopic 3D Gaming

September 13th, 2012 · 10 Comments · GeForce 3D Vision

If you have an older PC that you haven’t upgraded for a while and consider finally doing that in order to be able to play games in stereoscopic 3D mode you may think that you need to really do a serious upgrade of pretty much everything. And while you may not be that wrong in such an assumption, if you still have a decent processor and enough system memory the only thing that you may need to replace could be the video card in order to “get into the game”. The truth is that in the last few years the GPU has become way more important that the CPU in many areas and when talking about gaming and stereoscopic 3D gaming in particular it is even more important. With a high-end graphics card you may be able to get a good stereoscopic 3D experience even if you processor is not the latest generation and doesn’t have four or even more cores. The reason for that is that we’ve reached a state where the processors have become quite powerful performance wise, so that not that many programs (excluding most professional apps) can take full advantage of them… and the truth is that most games are not able to yet fully utilize the full performance of all the cores in a powerful processor, even if you play them in stereo 3D mode.

Lets not just talk about that, but give it a try to see how does the CPU performance affect the game performance in stereoscopic 3D mode. As an example I’ve used an Intel Core i5 2500K processor (3.3GHz Quad-core Sandy Bridge), on an Asus Sabertooth P67 motherboard, 4GB System Memory, and two GeForce GTX 580 video cards running in SLI mode under Windows 7. What I’ve done is to run five different recent and more demanding games on this setup at 1920×1080 resolution, maximum detail levels with no AA and in stereoscopic 3D mode using 3D Vision with the CPU at the default 4-core state (not overclocked), and then disable one, two and three of the cores so that the processor will behave as a single, dual, triple and quad-core. At each of these four states I’ve ran a benchmark and recorded the framerate as well as the CPU load of all of the available cores in each situation and you can see what are the results below…

As you can see from the table with results the situation is bad only when just a single core is enabled, the CPU load is hitting 100% while playing a game and the framerates are very low as clearly the processor is not able to deliver enough performance for the video cards to be utilized at their maximum potential. Note that the framerate listed is the average one in stereo 3D mode (the per eye value) and the CPU load in percentage is the one from all available cores. When we have two cores active not all games are hitting the maximum processor load and we can see up to double the framerate in some games as compared to when we have just one core, so clearly Dual-Core is the minimum for a decent experience nowadays. Going to three and four cores active we can see that the CPU load is gradually getting lower and the framerate is going just a little bit higher and the difference between 3 and 4-cores is even smaller.

So even if you have an older Dual-core processor you might still be able to enjoy good performance in games, even in stereoscopic 3D mode by just upgrading your video card to a more powerful and recent model and leaving your older CPU, motherboard and system memory for a while longer. So better spend on upgrading the video card now, instead of upgrading the CPU, motherboard and RAM at the moment and leaving the VGA upgrade for a later time if you have a more limited budget. As I’ve already said, the video card is way more important for stereoscopic 3D gaming compared to the processor, so with a more powerful GPU and not so powerful CPU you can still get good performance in games. Of course if you want to push for SLI with more video cards, go for multi-monitor setup and especially for multi-monitor combined with stereo 3D, the faster – the better, but again the video card(s) remain more important that the processor for gaming. So consider that the next time when you think about upgrading your gaming PC.

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10 responses so far ↓

  • 1 Shivoa // Sep 13, 2012 at 16:31

    Great research, always good to see numbers for modern games with a 120Hz cap (60fps stereo) using a lot of GPU power and limiting the CPU to see where it really hurts. I suspect there’ll be a lot of worth to repeating stuff like this in a couple of years when the new consoles are not limiting the game loop for new titles (unlike the potential issue right now where the game loop has to run on a 360 or PS3 CPU as well as on a PC).

    It also shows that nVidia should be putting more weight behind 3DVision (working with devs so when they ship a 3D game it actually works well; more work with fixing games using drivers – something they do a lot of work with for non-stereoscopic fixing and performance increases; pushing the hardware and getting more partners involved) because it is definitely in their interest to push something that doubles the GPU requirements of a system while not adding extra burden to the CPU.

  • 2 dandare // Sep 13, 2012 at 22:05

    hi bloody! / i got core 2 quad q6600 2.40GHz + GeForce 460 GTX + 4 gb ddr2 / please tell me in your opinion can i upgrade my videocard without q6600 becoming a bottleneck and if it is at all possible what most powerful card would you recommend!? thx!

  • 3 sfmdff // Sep 13, 2012 at 22:20

    Thanks for this great info. Have you done any similar testing on 3DVision Surround? I recently upgraded to a GTX 690 for my 5760×1080 setup, and definitely now see limitation from my 4Ghz Core i7 920. Trying to overclock more and looking into upgrading to an X79 setup to push towards 5Ghz.

  • 4 Bloody // Sep 14, 2012 at 08:23

    dandare, the faster the better, but something like at least GTX 660 Ti and as long as you are using a single 3D monitor you should not have much of a problem with the CPU performance.

    sfmdff, haven’t done that on a 3D Vision Surround setup, but there the demand for performance from both the GPU and the CPU is higher for sure.

  • 5 Dan Fury // Sep 15, 2012 at 15:53

    That was true before Guild Wars 2 came out. I have a Q6600 and had no need to upgrade it until now. My GTX 560 TI could play it without a problem, but my old quadcore and my DDR2 rams are holding my system back, so that I have 20fps instead of 40.

  • 6 Bloody // Sep 15, 2012 at 18:55

    Is true if you have a fast video card or get one, if your GPU is the limiting factor, then even with faster processor you will not be getting that much of an improvement. Going for GTX 660 Ti and remaining with DDR2 and the Q6600 should still give you higher FPS than if you upgrade your processor and continue using GTX 560 Ti.

  • 7 eqzitara // Sep 15, 2012 at 22:04

    Great stuff, its good to see numbers. I pretty much upgrade video card near once a year and processor/etc every other year.

    Someone taught me this and saved me a lot of headache.
    A good way to check if its your processor that is your “bottleneck” and not your videocard is to leave all settings at max and go to lowest resolution. Use fraps and FPS, now go to a higher resolution(your desired). Then see if FPS is the same. If it is nearly the same its your processor.

  • 8 Jett Stiles // Sep 16, 2012 at 21:45

    I really wonder if thats true for all games – I got a GTX 670 and an Athlon x6 1075T stuck together with 8GB RAM.

    When upping the setting in World of Warcraft f.e. I do get around 50+ fps in 2D mode but as soon as I turn 3D Vision on there are areas where it drops to 10-14fps (flying over SW for example).

    Even in not so populated areas I never get more than roughly 40fps which really makes me wonder if there isnt another bottleneck?

  • 9 Bloody // Sep 17, 2012 at 12:31

    Have you tried monitoring the CPU load and the GPU load while playing to see if any of them is maxed out or maybe both are? Also things like pushing high AA for example can lead to significant performance drop…

  • 10 Jett Stiles // Sep 19, 2012 at 18:03

    aye – the first CPU core sometimes hits 100%, the second one sits working around 75%. (The other four aren’t doing anything it seems – always thought WoW utilizes more cores?)

    As for the CPU: Even under stress it won’t go higher than 65% according to the Asus utility.

    Guess that means something could be off with my CPU?

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