Can We Get Acknowledgement of the Pimax Specific RTX 4090 Latency / Lag Issue please?

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8KX Lag / Latency Update

I just wanted to share my findings while troubleshooting this problem that cropped up since upgrading from RTX 3090 to 4090, that post can be read here if you have not already:

8KX, upgraded to RTX 4090 from 3090, weird lag latency that I cannot rectify.

My troubleshooting consisted of:

  1. Fully uninstalling SteamVR which consists of the SteamVR folder and the steamVR.settings at ProgramFiles (x86)/ Steam/ Config (2x actually as the problem persisted after the first full uninstall)
  2. Disabling both MSI AB and fpsVR
  3. Disabling HAGS
  4. Ensuring SteamVR process priority is set to Very High Priority in Task Manager.
  5. Swapped the USB and Displayports that the Pimax 8KX is using.

The problem persisted, so having felt that I sufficiently ruled out SteamVR I pulled my HTC Vive Pro 2 out of the closet, reinstalled it’s associated software, did the fully set up to get SteamVR to recognize it, repaired the Index Controllers to it and wouldn’t you know it, THE PROBLEM EXISTS THERE AS WELL @ 120 Hz no less.

The same exact problem, moderate, nauseating latency and a frame skipping problem every 5-10 seconds (the frequency of which is reduced by closing MSI AB, fpsVR has no bearing on this).
So I did more sleuthing, using the search terms “VR Latency Lag RTX 4090” and wouldn’t you know it Varjo Aero owners are also experiencing the same problem and Varjo has even come out and acknowledged that there is a problem and that they are working on it.

Excerpt:

"On 10/14/2022 at 2:13 PM, Supmua said:So Pimax also stutters at max FOV? What’s the common denominator here, NVIDIA software?

I think the current line of thought is it’s a driver issue at high throughput…possibly DSC related. Which likely means an Nvidia fix ???
Edited October 14 by zildac "

So the problem is most definitely real, affects all headsets, and is most definitely related to the RTX 4090, most definitely implicating the display driver and possibly pertains to the way DSC (Display Stream Compression) works.

If Nvidia reps could investigate and acknowledge and open up an escalated dialog with Nvidia that would be much appreciated, as I stated in my original post, I didn’t need more raster or RT with a 3090 at 5120x144 2D, my main justification for blowing $1600 US on this upgrade was because my 3090 struggled with VR across many demanding titles. How Nvidia dropped the ball with this is beyond me.

Thanks for reading.

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yeah in one of my posts above in reddit or maybe it was the vive forum. Someone said Nvidia changed things in the rendering pipeline and said they forgot to notify ppl.

So imagine Nvidia will need to work on a fix and communicate collaborate with hmd makers on what maybe needed to update there end if needed.

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Update:

It’s something related to DSC because the problem is not present with my Vive Pro 2 at 90 Hz but is present at 120 Hz. With my 8KX, reducing FOV from Large to Normal does not alleviate the issue. That reducing the refresh rate on the VP2 from 120 Hz to 90 Hz tells me that this issue is related to DSC.

Also, another bizarre issue is that it doesn’t matter if I change the resolution within SteamVR to 150% or 200% the GPU load is always 35% in VR Home (5800x3600 or around here). What is bizarre is that with my VP2, with an indicated 4380x4380 (this is what it is defaulting to at 100%, actual resolution is around 2500x2500!) and GPU load is at 65% in SteamVR and I actually have to reduce settings to lower than that of the Pimax 8KX in Assetto Corsa Competizione! Rough math puts the indicated resolution of the 8KX around 18k pixels vs maybe 17k of the VP2 but the load is way higher on the VP2! I have no idea what is going on here and I’ve already completely uninstalled SteamVR twice. Not sure if this is a Pitool problem or an Nvidia display driver problem or a SteamVR problem but if I had to guess I would say that it’s an Nvidia problem because I had none of these issues before upgrading to the 4090 and that’s the only variable that has changed.

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I tried to post this at r/nvidia but they took it down “Rule 1 no troubleshooting” and I an unable to submit a ticket to Nvidia (always returns “Error”). If anyone has open comms with Nvidia and can relay this problem that would be great.

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MSI AB has no bearing whatsoever on this issue. It’s something related to DSC because the problem is not present with my Vive Pro 2 at 90 Hz but is present at 120 Hz. With my 8KX, reducing FOV from Large to Normal does not alleviate the issue. That reducing the refresh rate on the VP2 from 120 Hz to 90 Hz tells me that this issue is related to DSC. I can leave MSI AB enabled on my VP2 @ 90 Hz and the problem is not present.

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Also, I neglected to add that my 8KX is running at 90 Hz, this is important as it has this is the determining factor as to whether or not the issue is present on my Vive Pro 2. At 120 Hz, the same identical problem, nauseating latench / lag with a frame-skip / stutter every 5-10 seconds (no corresponding frame-time spike, happens with 35% GPU load!) but at 90 Hz the issue is not present.

There is a possibility that those who say they aren’t having the problem with 8KX are at 75 Hz.

Again, reducing FOV from Large to Normal does not alleviate the problem for me. Similarly, reducing the indicated resolution from 4382x4382 to 2500x2500 on the VP2 also does not alleviate the issue. The only thing that alleviates the issue is reducing the refresh rate.

I haven’t tried reducing the refresh rate from 90 to 75 Hz on the 8KX because I’m afraid I may brick the headset as it’s quite finnicky with this setting. I’m hoping this issue is resolved quickly, in the meantime I’ve fallen back on my VP2 which has nice contrast and clarity in comparison albeit runs uncomfortably hot.

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I’ll at least say that I’m on 90hz.

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Also 90Hz, but Normal FOV and higher Resolutions (4000+ pix vertical)
In order to bring my GPU load into normal paths, I use increased pixel density in the games, otherwise I only hang around at half load. (10850k @ 5.0)

Have you checked the speed for the PCIe bus and the protocol in the motherboard bios? If you have 4.0 switch it to 3.0 /16. Just a tough.

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I’m at 90Hz and working fine.

Not necessarily.

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I have tried the 8K X at wide and normal FoV, refresh rate at 90hz, 75hz & 60hz and the lag is always there.

FYI I have logged a ticket to Nvidia and they have said they are not aware of any such problem and have not made any changes that would affect this. They say this has not been reported to them so are treating it as a single user problem.

They have asked for system logs so I will provide today and feed back here any findings from Nvidia, but at this point they are saying there is no such issue.

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I would urge folks to log an Nvidia ticket so they’see it is not just me having the issue.

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I wish I could, the portal where you do this always returns “Error” after I log in. It’s weird because as I said, if I reduce the refresh rate on my VP2 from 120 to 90 Hz the problem completely disappears. Unfortunately, as you said, no changes whatsoever alleviate the issue on the 8KX.

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I will try this, thanks for the suggestion, GPU- Z shows 4.0:

GPU Z
GPU Z388×539 59.8 KB

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Why else would the issue not be present at 90 Hz and only at 120 Hz on the VP2? That sounds like a bandwidth problem. HelioSurge confirmed that Nvidia stated that they forgot to tell HMD manufacturers that DSC works differently now or something along these lines?

GPU load is not 100% at 120 Hz, it’s not GPU load, it’s the same exact problem as on the 8KX at 35% GPU load a floating, delayed lag / latency and a skipped frame / stutter every 5-10 seconds. These aren’t frame-time spikes and the GPU is not under strain.

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I wonder why some people have this issue and others not?

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I don’t think it’s any of those utilities, hear me out, at the initial stage of troubleshooting this issue this was the go to retort: “Disable HAGS, close MSI AB and fpsVR” I did that and closing MSI AB DID reduce by not completely eliminate the issue on my 8KX (now it happens every 20-30 seconds instead of every 5-10) BUT on my Vive Pro 2 @ 90 Hz where there is no nauseating lag / latency issue there is no need to close MSI AB because there also isn’t any frame-skip / stutter whatsoever. Closing MSI AB does nothing.

Also, the same exact latency / lag + stutter described here is present at 120 Hz on the VP2 but not at 90 Hz leading me to conclude that it is indeed related to DSC!

Going by your information, maybe it’s as though the system becomes susceptible to monitoring tools introducing stutter beyond a certain refresh rate and resolution amount, the old adage about a match breaking a camels back.

Also, if you have the frame-skipping / stuttering there is a possibility that you also have the latency / lag and just don’t realize it, aren’t sensitive to it. I don’t know how you would not notice it though, it’s pretty bad, especially when looking up and down.

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That’s why I’m asking everyone for more information, initially I thought it was just the 8KX, this issue also affects Varjo Aero owners and affects my Vive Pro 2 at 120 Hz (but is not present at 90 Hz!).

Possible variables:

  • Hardware version (I have the older 2075 version that cannot be flashed to 120 Hz firmware)
  • OS: (I’m on Windows 10)
  • System Memory type: (I’m using DDR4, fast and low latency C15 DDR4)
  • Display Driver version (526.61 clean installed with DDU)
  • Geforce Experience running: (It is not running on my system)
  • Refresh Rate: (this is the only variable I have confirmed on my end with my VP2)

There’s also the possibility that those who say they don’t have the problem aren’t running MSI AB and actually do have the lag / latency problem and are simply not sensitive enough to feel it. If I close MSI AB the frame-skipping frequency reduces from once every 5-10 seconds to once every 30 seconds or so and you can, kind of, get used to the latency but honestly it’s pretty bad, so bad that I’m currently using my VP2 which does not have these issues at 90 Hz.

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I had that error too but I tried again and it worked.

Maybe persevere - I got two emails for a security two factor authentication, one worked, the other didn’t. They one that worked I opened the Nvidia portal in the same browser.

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I think you have a reasonable theory. I’m just cautioning you to not decide that it must be true only because you can’t think of any other possible cause. As a user on the outside, you have limited insight and access into what’s going on in the internals. It could easily be something else not functioning as intended that you don’t even know exists because it’s an internal engineering detail.

Accurately diagnosing the issue is likely to require the engineering resources and proprietary knowledge of nVidia and possibly Pimax and other companies as well.

I noticed the issue quickly, but at least on mine it was very subtle, and I wasn’t sure (and frankly still am not sure) if I was just being hypersensitive because of installing a new GPU. There are likely different amounts of latency on different setups and also varying user sensitivity to it. A user will notice it only when it’s bad enough on their setup to cross the threshold of their noticing it.

This response is likely to have come from a support person who may not know whether nVidia’s dev is actually aware of or working on the issue. At best, it indicates that there has not been a general notice within nVidia that this is a problem.

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Just checked the ongoing recognized issues in Nvidia’s latest display driver notes and this issue is not acknowledged at all.

Going by the feedback in the Vive Pro 2 thread I created, there are a lot of people corroborating this issue:

Notable comment:

level 1

·15 hr. ago

My varjo aero had similar problems with 4090 untill varjo updated their drivers. It works great now and had something to do with the way compression is handles in the new cards. I suppose it’s up to htc and pimax to fix their stuff

So Varjo had the problem and it was rectified with a firmware update.

Is this an Nvidia or Pimax, HTC, other HMD manufacturer problem?

The aforementioned comment would lead me to believe it’s an HMD manufacturer problem and therefore the solution can only come by way of a firmware update.

Seeing as how it took Pimax over 6 months to fix their Tundra tracker assignment problem, looks like I will be using my VP2 in 90 Hz mode until some time late 2023.

The irony is that I justified upgrading from the 3090 to 4090 because of trying to run VR in the 8KX, I had zero need for more RT or raster at 5120x1440 2D.