I've never been able to get it to be playable with DK2. The judder is insane. I was using a 660Ti and recently switched to a 980. The exact same problem. Head movement is awful. Everything is smooth and fine if I never move my head. If I put the graphics settings all the way on Low it's playable but not very good. I would assume a 980 could do this game but maybe not? I'm using extended mode as well. Anyone else get this to work smoothly? If so what settings did you use?
ETS2 was one of the easiest things for me to get to work. I followed the well-documented instructions about opting into the correct beta version in Steam and adding the -oculus command line parameter. Then I set the Rift as the primary display and ran the game. It's not perfectly judder free all the time, but most of the time it's very smooth. My system is an i7-4770 + 780 x2 SLI.
When you're having bad judder and you can't figure out why, one of the first things you should do is find out what framerate the game is actually rendering at. You can use the framerate logging feature of Fraps, or the overlay on MSI Afterburner, or something like that. Whatever you do, get an actual numeric measurement. If the game isn't running at or near 75 fps, then you know you're doing something wrong. If it's running at or near 60 fps, that's a good indication that you really need to set the Rift as primary before running the game, because the game is syncing to your main monitor's refresh rate (typically 60Hz) instead of the Rift's. Of course, there are all kinds of other problems that can cause judder, but knowing the actual framerate you're getting can be a good step in tracking down the problem.
I'm running the ATI 7870 with this one, a slightly older card, and I'm not really having any problems. I get a little bit of judder, but not that much really, and it's certainly not unplayable.
My advice mirrors what you'll find elsewhere really. DK2 in extended, make it primary. All monitors 75Hz refresh rate, and check the game's also running at 75Hz too (even when they're all properly set to 75, I still have stuff default to 60). In your graphics card settings, turn VSync on and Triple Buffering off.
It's a pity you're having problems, because, for my part, it's probably what I've enjoyed playing the most.
OK. I'll look into these suggestions. I already have it in extended mode and the rift is the primary monitor. Both the rift and my monitor are refreshing 75Hz. Vsync is on in the geforce control panel as a global setting. Eurotruck is running with the Oculus parameter and I've opted into the VR beta for it as well. It still sucked on a 660. I upgraded to the 980. Exact same experience. I'll try any other things that were suggested and go from there.
Vsync off is a bad suggestion as it causes tearing and uneven frame timing. 75 fps with a cap does not result in lower latency than 75 fps with vsync. Why would the Oculus SDK and best practices be designed around using vsync if it adds latency?
Your code should run at a frame rate equal to or greater than the Rift display refresh rate, v-synced and unbuffered. Lag and dropped frames produce judder which is discomforting in VR.
Vsync should be on unless you're benchmarking or are unable to maintain the target framerate. In the latter case, it's better to use adaptive vsync (set in the NVIDIA driver settings) than no vsync, so you can get the benefits of vsync when you are reaching the target framerate and avoid the drawbacks when you aren't reaching the target framerate. In case there's any doubt, by target framerate I mean the refresh rate of the display, 75Hz for DK2.