AMD & NVIDIA GPU VR Performance: Valve's Robot Repair

Author:Kyle Bennett

Date: Monday , August 15, 2016

Robot Repair is a mini-game that you can download for free from Steam to use with your HTC Vive VR system. It is highly likely that anyone using a new HTC Vive will play the mini-games inside Valve's The Lab. This is a Source 2 engine demo and perfect to validate prior GPU performance we have tested.

What is Valve's The Lab: Robot Repair?

If you have an HTC Vive VR system, you can download and play The Lab for free. The Lab is a series of eight "mini-games," some of these are demos and some are actual games. I played through all the mini-games this week and found Robot Repair to be the most GPU-intensive. Longbow is my favorite and certainly the "most playable," and I highly suggest you give it a try, but that is besides the point.

Robot Repair being the most stressful in terms of GPU Render Times should come as no surprise since this is the demo that Valve uses for its SteamVR Performance Test.. You can run this test on your PC at home to find out the following:

The SteamVR Performance Test measures your system's rendering power using a 2-minute sequence from Valves Aperture Robot Repair VR demo. After collecting the data it determines whether your system is capable of running VR content at 90fps and whether VR content can tune the visual fidelity up to the recommended level. For machines that are not VR Ready the tool can help determine whether capabilities are bound by Graphics Card, CPU, or both.

Given that this portion of The Lab is used in the SteamVR Performance Test, I think no one will be able to argue that either AMD or NVIDIA have not optimized for this test in its drivers. This marks our fourth VR performance review, with Raw Data, The Gallery Episode 1: Call of Starseed, and Trials on Tatooine coming previously.

Adaptive Quality is a technique used to keep your GPU Rendering Time low enough so as to not for Reprojection. It has been discussed that Robot Repair uses Adaptive Quality in order to help keep your framerate as close to 90fps as possible. One video seems to show this. I personally could never see evidence of this Adaptive Quality being used with our sample of GPUs, while I was playing this mini-game repeatedly, and our GPU Render Time scaling and Reprojection instances do not seem to show huge impacts either when compared to our previous in-game data collections. This may be because we are not using GPUs far enough down the scale to trigger this technique.

Alex Vlachos from Valve discussed this at GDC as this however being used as a technique that was being put into effect, so I have to believe that it is being used to some extent with specific video cards. Adaptive Quality can scale rendering resolution, viewport size, and anti-aliasing levels among other things like Fixed Foveated Rendering and Radial Density Masking if those are programmed for. That all said, after using Robot Repair over and over again, it seems to be a good demo for us to use in our HardOCP VR Leaderboard results.

This demo uses Valve's Source 2 Engine. Valve has since moved to the Unity Renderer for all its in-house work.

Source 2, announced early last year at GDC 2015, gave some gamers hope that Valve would be getting back into new game development. So far, the only retail game that utilizes the Source 2 engine is Dota 2 آ– Reborn. Additionally, within Valve’s VR demo The Lab, you can play an experience called Robot Repair. While all of the other experiences within The Lab were created using Unity, Robot Repair runs on Source 2.

If you want to see the demo being played through you can see it all on the video below. However, if you are planning on purchasing an HTC Vive any time soon, I would suggest waiting to experience it in VR for the first time.

Much like we saw in Trials on Tatooine, Robot Repair is not forgiving in terms of Reprojection like Starseed or Raw Data are. Robot Repair takes place in very brightly lit environment like ToT, but is slow moving like Starseed. However, the frame judder introduced by Reprojection is only extremely apparent when the robot and its extended parts are animated and you open and close the drawer containing the "pocket universe." When we drop frames when closing or opening the drawer, these dropped frames are extremely apparent.

It occurred to me while writing this that I have talked a lot about "frame judder" but have never shown this to you. Below is a slide specific to Rotation-Only Reprojection, but shows exactly what I am talking about when I refer to frame judder and gives a quick explanation. Frame judder appears as a shadowed or somewhat blurred image in your HMD (Head Mounted Display).