Pimax Crystal Sim Performance Settings

[Glide]

I discovered some really nice performance settings in the sim today.  They may seem odd, but give them a try if you can. 

My settings are below.  As you can see I had to turn them down quite a bit in order to maintain an App GPU time below 33ms.  With the FPS locked at 30 in the Settings, I was getting an App GPU time of around 24ms.  This gave me a LOT of headroom for spikes in performance, and as a result I got a very, very solid 30 FPS.

Here are the key ingredients: no AA, no AF.  I am running a custom resolution of 3500x4142 on my 3080Ti, so the alaising was very minimal to begin with.  Enable Smart Smoothing in the Pimax Play Client.  I am running 72hz Lab Mode right now. Only thing set in the Nvidia Control Panel is Low Latency On.

No Quadviews, No scaling in OpenXR Toolkit, no Foveated Rendering.  Just pure frames with Smart Smoothing, and whatever settings you need to keep the App GPU time around 24ms.  Clear, and smooth.  (Update: even better settings below)

 

Edited March 12, 2024 by Glide

[Glide]

Okay, while those settings were good, in missions that are a bit busier, they can be a bit bumpy. 

Even better: Disable Smart Smoothing in the Play Client.  Enable Prefer Framerate over Latency (turbo mode) in the PimaxXR client.  Disable Low Latency Mode in the NCP (not sure if this conflicts with turbo mode).  This allowed me to bump up the FPS to 35 in the Settings.

So, in exchange for very little aliasing, no ghosting, the best sharpness you can get (the spotting "dot" is clearly a square with these settings), and perfectly smooth framerates.

I still need to test a few more maps and missions.

I would love to hear what the 40 series cards can do with these settings and maximum resolution.

[HoBGoBLiNzx3]

with the 4090 I have 72 hz no smoothing, dlss and quad views @ 185% and it's fking diiiaalllled. Finally got it just right the past hour.

[Glide]

Yes!  So, I lowered my resolution to 2880x3408, and this gave me even more headroom.  This headset works excellently at lower resolutions.  Then, to eliminate the jaggies, MSAA X4 and Quadviews, and it's perfect.  No ghosting and smooth flight.  Can't tell from the FPS counter from OpenXRtk what the app GPU time is, but is never moves from 35/36 fps during my busiest dogfight.  Now to bring back some of the graphic fidelity from the Settings, and these are set and forget.

Edited March 12, 2024 by Glide

[Glide]

One final tweak, I brought the resolution back up to 3500x4142, and I might drop MSAA to X2.  The key takeaway for this method is to watch the App GPU time.  With the FPS locked at 30, if you are seeing 33ms frame times, then the GPU is working as hard as it can.  If you see 24 ms frame times, you know you have 9ms of headroom before the GPU may skip a beat and you get a stutter.  Tweaking the resolution allows you to find the limits of your hardware.  Then with Quadviews and/or some DLSS type scaling, and you can bring the visuals back into the sim.

[Glide]

So, I was reading about how some upscale the headset and use DLSS to fit the resolution on their hardware.  I set a custom resolution of 4700 in ORXTK, and then worked my way up to DLSS Quality.  This took me to 103% of my VRAM, which causes stutters during missions when memory starts swapping.

Dropping Textures to Medium, Terrain Textures to Low, and Shadows to Medium, brought me down to 70% VRAM usage with DLSS Quality.  So, you can upscale the headset quite nicely.

 

[Glide]

That 4700 number was from a 4090 owner, so for my 3080Ti, I dialed it back to 4500.  With DLSS Performance I get VRAM usage in the 70's, and I hold a rock solid 35fps.  DLSS Balanced pushed my VRAM consumption almost to 100%, and that's too close for comfort.

[j9murphy]

for me the magic formula for the crystal with the latest DCS update is:

• Crystal Resolution = Max
• Set Crystal refresh rate to preference (for me that's 90hz)
• PimaxXR - Prefer framerate over latency
• Quadviews = set resolution of center to 100%
• OXRTK - all options to default (I'm evaluating the relative benefit of continuing to use this at all)
• DCS - Pixel Density = 1, set max DCS fps equal to HMD refresh rate, no DLSS/MSAA/DLAA

For me, this creates the ability to turn up the graphics in DCS so that almost everything is on/max with steady framerates and no ghosting or stuttering.

(4090 / 13900k)

 

Edited March 15, 2024 by j9murphy

[Glide]

Interesting tests today.  My goal was to get my 3080Ti to run Maximum resolution, and so I started tuning my settings accordingly.  I started out with nothing enabled in PimaxXR, no OpenXRTK enabled, just dlss performance, and my light performance settings from above.  I wanted to check again how Smart Smoothing works.  I found that it doesn't show very many of those vsync-like screen artifacts when it's BELOW half the refresh rate.  When I could hit say 45fps, I believe the Smart Smoothing was struggling a bit.  You can see some evidence in the FPS counter when the screen artifacts appear.  Kind of a de-sync pattern for a second or two. The screenshots are not great.

Then I turned on Low Latency Mode to On (Ultra did not make any difference).  Now, I started to see brief periods where I would go from CPU bound to GPU bound with a theoretical FPS of 110ish.  But, it would cycle back and forth, perhaps indicating that Smart Smoothing was struggling.

Then I turn off Smart Smoothing, and the FPS counter stayed solidly on GPU bound theoretically fps 110ish thanks to Low Latency Mode.  If I want to go higher, I need more VRAM because I can hit 12gb with this resolution quite easily.

Low Latency Mode On

No Quadviews, no Smart Smoothing, no Dynamic FOV rendering and no scaling.

Note: I am also testing Eye Tracking OFF and Auto IPD OFF to see how that effects stability, but I don't think it was a factor in this test.

[HoBGoBLiNzx3]

With the release up 72hz upscaling on the crystal light (and soon to be released for the OG crystal) I'm assuming you can not use DLSS along side with this option? Curious the difference in frame rate and clarity between the two, or if they can be combined for even more performance.