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After a relatively long hiatus and a long series of hardware and software updates I have a VR rig that’s working extremely well.
However, at some point a problem crept-in with vorpX that I’ve yet to solve:
Fast and Alt Fast Sync used to work just fine to my Pimax 5K+ for me on my older rig, but on this one neither of those methods is working reliably. I’m getting flickering scenes, lack of sync, different frames in each eye, and that kind of thing. And while it’s somewhat related to overall GPU usage, it’s not any kind of a direct correlation (see below).
Important rig details: Ryzen 5900X and RTX 3080 Ti, 32GB ram. I’m on PiTool v.1.0.1.272_20210917, which I believe is a release-version (non-beta; or at least as non-beta as anything out of Pimax is!) Video drivers are up-to-date (and this issue has survived several updates thus far.)
I have excellent performance in native VR titles and things run nice and cool. I can push the GPU to nearly 100% all the time and it generally won’t even hit 80 degrees c. CPU likewise stays nice a cool (of course, it’s often sitting there not doing a whole lot in GPU heavy games anyway.) For example Alyx runs at 200+ Steam SS in Wide FOV totally without issue and often sees GPU usage clear up at 95+%. Cyberpunk (on my 3D display) will again run at 95%+ for hours. So I’m convinced this is a software issue, possibly an incompatibility between vorpX and my PiTool version? I’ve also tried manually under-clocking my GPU, just in case. Made no difference (beyond reducing my performance.)
More info: This issue *does* depend on the title: I’m having zero issues with Greedfall for example – I have it running at 72hz in virtual cinema mode with no motion smoothing. GPU is often pegged way up above 90% in this title, and everything remains perfect. In FO3 however, I’ve had to switch to “Safe” sync mode. Same for Cyberpunk. The problem worsens with either kind of motion-smoothing (vorpX or Brainwarp) enabled, but is not completely related to motion smoothing. It’s also somewhat related to total GPU usage, but it’s again not completely related to total GPU usage (see Greedfall example above). Both Fallout 3 and Cyberpunk are good examples of titles where I’m seeing this behavior, and I’m having to leave a huge amount of GPU power on-the-table now to get these games to display properly as I’ve now got both of them in Safe sync mode. In Fallout 3 I was pushing 4K, G3D, 45fps/90Hz using vorpX motion smoothing, on my 2080 Super with no issues. Now, on my 3080 Ti those exact same settings result in sync-glitches. (I currently have it running safe Sync mode, 64Hz, no motion smoothing). In Cyberpunk I’m having to leave tremendous GPU overhead in order to maintain a properly synced experience, since Safe mode causes the FPS in the game itself to drop considerably and either of the faster HMD sync modes causes significant sync issues. I can push the GPU usage a bit higher with motion-smoothing off before this issue presents itself. For example, in Cyberpunk, Fast or Alt Fast sync mode, motion smoothing ON, I might start to see this clear down around 50% or 60% usage. With motion smoothing OFF and still in Fast or Alt Fast sync mode I might be able to push as high as 70% GPU usage before I start to have problems. In Safe sync mode all is good but of course my overall frame-rate suffers greatly. I haven’t tested Fallout 4 yet (I have the VR version now, so I’m not really using vorpX for F04 at this point.) I’ve picked-up Life is Strange True Colors recently, so I’ll test that soon.
Sorry for the incredibly long post, but it’s a weird issue and varies considerably title-to-title.
Is there a specific PiTool version I should be trying to use? Any other info on how I might try to get Fast or Alt Fast sync modes to work correctly again?
Thank you!
How odd. I get more or less 100% GPU utilization with CP2077 here with Fast Sync. (measured with nVidia Inspector). Don’t use the Windows task manager, the GPU usage shown there is often garbage. Also just in case: NEVER EVER run external GPU tools (e.g. Afterburner or similar tools) that hook the graphics pipeline alongside vorpX as that may cause performance issues itself. nVidia Inspector is the best tool to measure GPU utilization since it doesn’t hook the graphics pipeline.
BTW: ‘Safe’ leaves more GPU resources for the headset render thread at the cost of reduced framerate. That’s not an issue, it’s the purpose of the method. If you crank everything up to max, so that there aren’t enough GPU resources available for the headset render thread to run reliably in parallel, the fast sync modes can cause judder. Switching to ‘Safe’ may help in such a case.
Thanks Ralf, I went through and double-checked for these types of apps and then fully uninstalled every single *anything* that potentially mucks around with GPU functions or overlays in any way. Even FPSVR, which I’ve long used with no ill-effects. (Amusingly, now that I’ve reinstalled FPSVR it has returned to functioning properly in native VR games but has stopped working in anything that uses vorpX; it just no longer displays. Oh well. Tackle that one later.)
No luck, I still get very poor HMD sync in Fast or Alt Fast modes and I’m worried at this point it may be one of the later HMD firmware updates from Pimax. There have been two of those fairly recently. I’ll run through installing some older versions of PiTool itself first, but I’m not hopeful.
I’ve got plenty of old SSDs just hanging around unused, so what I’ll do sometime soon is a complete clean-install test-run; Just Win10, PiTool, GPU drivers, vorpX & Steam/VR. It’s not a scenario that I look forward to, because if it works it’s going to mean countless hours manually migrating only my essential settings back to an otherwise clean install, but unless you have other ideas I think I’m at that point.
Not sure what else to say than what I said above already: you probably just overload everything by cranking up settings too high. vorpX has to handle two things in parallel: the game rendering and its own render thread, which feeds the image to the headset. When you overdo it on the game side, it gets impossible for vorpX to maintain a solid framerate for the headset render thread. Unfortunately there is no way for normal application developers like me to reserve GPU resources in a way that can guarantee a desired target framerate for the headset thread no matter what you do on the game side.
When you encounter a juddery/low headset framerate, you either have to find a balance between graphics fidelity and performance that works with the fast modes or switch to safe sync. That’s what it’s for.
BTW: Use vorpX’s built in FPS counter (ALT+F). It shows both the game and the headset framerate, ideally the headset framerate would always be your headset refresh rate (i.e. 90 for most headsets).
BTW2: In my experience a Pimax headset doesn’t exactly help with this matter due to the extra image processing/scaling they do in their own application, which essentially adds yet another rendering stage before the image finally reaches the headset.
Yeah, it’s certainly possible I’m just expecting too much out of my 3080 Ti, but it just seems strange to me that I could push my 2080 Super to very high GPU usage in, for example, Fallout 3, in fast mode, with no tearing or other issues and have to leave a much higher percentage of available GPU time ‘on the table’ with my 3080. It would not be the first time Pimax pushed a firmware and/or PiTool update that caused sync issues, that’s for sure.
And yes, I’m not a fanboy of Pimax and I’m quite aware of the limitations and foibles. Unfortunately my brain really doesn’t agree with the limited FOV of all other available HMDs, so I’m basically stuck with Pimax and seriously considering upgrading to the 8K X. I can’t wait for a better-established company to come out with a high-pixel-density wide FOV HMD (preferably one with a secondary processor in the HMD so that the HMD itself does the transformations necessary for wide FOV (i.e. ‘Parallel Projections’) and takes that load off our GPUs.)
Out of curiosity, with CPUs getting so fast now, is there any part of the process you could offload the the CPU?
Finally found a native VR title (Fallout 4 VR) that was behaving the same way, with weird sync issues at high GPU usage.
So eventually a full wipe and reinstall of Win10 ensued and that has fixed the issue with vorpX as well. I can now push the GPU fully without experiencing sync issues, and Fast modes are now working again in vorpX titles.
Unfortunately I was unable to discover what caused the issue originally. I think it may have been cruft of old PiTool versions, but ultimately no amount of uninstalling (even tracking down and deleting remnants manually), driver updating, or even an in-place re-installation of Windows resolved the issue.
First things first: please keep in mind that the ‘Safe’ option exists precisely for the purpose of dealing with GPU overload caused by cranking up settings too high. That’s what it’s for: it sacrifices a few FPS for better stability when you overdo things.
That said:
Incidentally I just spent the entire Sunday night (it’s almost 5am here) checking exactly this. Quite successful. Not only will there be a full frame less latency with ‘FluidSync’ enabled, which is great in itself. Almost more imprtant: with the ‘Fast’ headset sync it’s now a lot harder to tank the headset framerate below 90, regardless of GPU utilization. That’s for the most part what made things go haywire when you overdo things. At stable 30/90 plus the better latancy even 30fps are not only bearable, but actually quite playable.
Caveat 1: This does not fully apply to ‘Alt. Fast’, which is what DX12 always uses (‘Fast’ and ‘Alt. Fast’) are currently the same for DX12. I’ll check later today after a few hours of good sleep whether I can do something about that. At least The better latency also applies to DX12 though.
Caveat 2: Haven’t checked Pimax yet. Pimax headsets usually are somewhat more problematic in this regard, so not sure how things will turn out for Pimax.
“At stable 30/90 plus the better latancy even 30fps are not only bearable, but actually quite”
this sounds good :)
Caveat 2: Haven’t checked Pimax yet. Pimax headsets usually are somewhat more problematic in this regard, so not sure how things will turn out for Pimax.
Honestly, it’s just great that you even bother to check a HMD model with such a low market-share, I’m grateful! Still hoping some bigger names in the game come along and make a HMD with canted lenses. The Index, apparently, does need some equivalent to PP on rare occasions, but not often enough to force most devs to include proper rendering the game-engine.
Out of curiosity, which model do you have? I bit-the-bullet and upgraded to the 8K-X and the clarity is just fantastic. Even distant objects retain detail and smooth edges pretty darn well at 100% Steam SS, and performance is really not much worse (with the 5K+, to get clarity and smooth edges so much SS was necessary that the actual number of pixels I’m rendering on the 8K-X isn’t that much higher.) In well-optimized (Alyx, TWD) native VR titles I’m able to push Wide FOV at 90fps as long as Parallel Projections isn’t necessary. Even with PP on I can often get to 60fps, which is fine for something like Dirt Rally 2 and other seated VR titles. I’m pushing basically 8K per eye to Dirt Rally 2, wide FOV with PP on and have been able to maintain a solid 60fps.
I have a Pimax 5K here, which honestly is only ever used for making sure things work as they should in general. As you say, Pimax’ market share is just too low to justify more than applying some default values that I found working best for Pimax and considering the wider resolution while figuring out the automated resolutions in DirectVR games. That’s probably already infinitely more Pimax optimization than most other developers ever bother to do.
BTW: Requiring parallel projections is not such a big deal for vorpX as it is for native VR games. That only applies to the second render stage where the image is sent to the headset, which only costs a few milliseconds. Doesn’t affect the actual game rendering at all. Nothing you have to be concerned about performance wise. The only thing that really counts is dialing in sensible settings in a game’s graphics options so that the aforementioned second stage (the second number in the vorpX FPS counter) stays at 90fps whenever possible. Yes, yes, I know you don’t want to hear that. ;)
I have a Pimax 5K here, which honestly is only ever used for making sure things work as they should in general.
The only thing that really counts is dialing in sensible settings in a game’s graphics options so that the aforementioned second stage (the second number in the vorpX FPS counter) stays at 90fps whenever possible. Yes, yes, I know you don’t want to hear that. ;)
a) See if you can get Pimax to gift you a better one. You never know.
b) I do generally try to keep the frame-rate to the HMD right at the refresh rate. I don’t always run 90Hz, especially if I’m not doing full VR. I like the 60/75/90Hz options in this one better than the 64/72/90 – it gives me just a tad more range, and I think older games on especially fragile engines don’t *really* like to go above 60 (anything from Bethesda, *cough* *cough*.)
I only need a Pimax headset to make sure things are working, no need for anything elese than what I have here. Gifts always come with expectations. The main issue with Pimax in conjunction with vorpX is the ‘brainwarp’ software layer. Unfortunately no way to turn that stuff off entirely.
Wasn’t entirely clear above, sorry. What I should have said is that the second number in the vorpX FPS counter should ideally always be the refresh rate of your headset. If you select 72 in PiTool, it should be 72, if you select 90 in PiTool, it should be 90 and so on. vorpX works best when it can do all interpolation from the game framerate to the headset refresh rate by itself.
Unfortunately that’s where ‘brainwarp’ gets in the way. Pimax headsets are much less liekely to stay solid in that respect than other headsets and thus are more sensitive to judder with vorpX than other headsets. They just can’t deal well with an application that wants to do the game to headset framerate conversion on its own, pretty much like WMR headsets behaved over SteamVR before Microsoft came up with their totally awesome WMR OpenXR runtime.
Do you have the 5K Plus, XR, or Super? All of those should be pretty good HMDs, but I definitely get not wanting to fuss with the extra crap through PiTool / Experience.
I’ve worn quite a few HMDs, and unfortunately, as I’ve probably said, I feel so claustrophobic in all the standard HMDs that I’m pretty much stuck with Pimax for now.
I will say that in terms of overall image quality, my 8K-X is hands-down the best HMD I’ve ever tried. You can lookup plenty of non-fanboy through-the-lens comparisons if you want. Worth the investment for me, for sure.
But anyway, I did notice when I moved from the 5K+ to the 8K-X my performance through vorpX titles stayed *identical.* I don’t know why this should be, but I expect you are pushing the same number of pixels to the 8K-X as you did to my 5K+, even though I’m running the 8K-X in native mode (not upscaled). I’m not complaining, and you probably shouldn’t change how it’s currently working, as it looks very good and performs well. I just thought I would mention it in case it’s relevant for future versions of vorpX.
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