Quick thoughts on GPUs for VR

I see lots of speculation around about what graphics card you need for good VR experiences. At this point we are at least a few months away from availability of commercial VR systems for PCs. As such the advice I can give is pretty easy right now- wait if you can! If you absolutely positively need to buy a new graphics card now, go ahead. But if you can wait until you are actually receiving your VR headset things will be cheaper and there will be more information about upcoming cards, relative performance for VR scenarios and the needs of various titles needs.

In the end the answer won’t be straight-forward because it will all depend on content. Can you run VR with a HTC Vive with an older graphics card? Probably if all you want to do are more simple experiences. Heck, you could almost get the required 90FPS on an integrated GPU if your scene is just a simple cube (but maybe not quite). But the key thing is that you REALLY NEED to make 90fps. All the time. Techniques like async time warp are interesting but they have really visible artifacts when used with positional tracking and if you have tracked controllers they will be VERY noticeable (since every timewarp your controllers will glitch in their positions). Good experiences in VR are more about consistent smooth motion that 100% matches what you expect even more than realistic rendering. For example one of the demos we show is Job Simulator where everything is a cartoon representation of objects. It doesn’t look like reality but the Owlchemy guys did such a good job with it that it FEELS like reality.

So what am I going to do for my personal rig? First of all, wait as long as possible. Second, I’m not going to cut corners. Like most tech VR equipment will great much less expensive in the future. But this is the first generation of real products and its not going to be inexpensive for a quality setup. In the past I have never bought a GPU for much over $300, but I’m expecting to spend in the $650-range for either a 980ti/equivalent or maybe dual slightly smaller GPUs since stereo rendering can do such a great job on dual-GPU setups. I know its a lot, but then again 15 years ago I used to have to spend $4000 for a high-end PC and the whole system with an amazing GPU should be less than $2000 now. Until now the difference between that $300 GPU and something better was really hard to tell for most people, but with these VR experiences it becomes worth it.

3 thoughts on “Quick thoughts on GPUs for VR

  1. The important issues are not about the artifacts of the timewarp itself (which are probably not noticeable as long as you aren’t timewarping every other frame) but rather about how it interacts with tracked controllers. With tracked controllers you would go from a butter-smooth “physical” feeling that the controller is exactly in the right place to a glitchy feeling where it no longer feels physical.

    Positional could help some maybe but if it were used too much it could be a problem. Take the first example in the comment above- the width of the adjacent wall to the right of the alcove varies quite a bit because it doesn’t have any information to fill in behind it. Again, to correct for one missed frame now and then its no big deal but if you did it constantly the world wouldn’t feel solid in the way we need it to for a good feeling of presence.

    In the end for me modern VR PCs should be able to render 90hz consistently and game engines should be scalable to adjust as necessary to hit that. I’d much rather have a small decrease in rendering quality than missed frames. In other environments (mobile/consoles) of course there are very different trade-offs.

  2. Also- to clarify one of the most exciting parts of VR right now. No one really knows what works best! The first generation consumer products haven’t hit the market yet and the use-cases are all over the place. So its certainly not true that one set of solutions will fit all scenarios and research on all of these techniques is really important. Presumably it will all play out over the next few years and we will learn a ton about the trade-offs of different approaches.

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