I suggest going to Pitool Category & Fill out the template in Bug Report Sub Category “judder”
I do not have the stutter/judder issue on 8KX or any Pimax for months now, not on desktop PC nor the 2080 laptop.
I had that issue a while ago (in August-September during the first EU trip with Pimax) but after cleaning upp all PiTool folders in Appdata and program files/ Program data folders and installing PiTool again, problem was gone.
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Yes thats correct. On 8KX the FFR is far from distracting in Balanced mode playing Skyrim for example. On 5K+ it was way more shimmery and obvious.
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Is there a big difference between using or not FFR?? How much percentage do you think?
I made a video about it long ago. It all depends on the game. Skyrim gets at least 10-15fps boost on Balanced mode. Some games can even get above 30% better performance, like Arizona Sunshine. Haven’t tested out much FFR lately with 8KX except Skyrim and it did give approx 10fps from what I could see.
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Have to confirm that unfortunately the stutters are still there even with this newest Pitool .245 on a 5K+ S/N 202*. Seen in games, Steam VR test screen, the Pimax home planet scene etc.as reported a million times already.
8K owners no need to report here as the stutter problems seem to be with the 5K+ models only. Might be a exclusive feature for the happy owners of the botched batch S/N 202* models like mine.
Here are my system specs:
Pimax 5K+ S/N 202* | Intel i9-9900K | Z390 AORUS MASTER | 32GB Corsair Vengeance LPX 3200MHz | Asus RTX 2080Ti Strix | 500GB Samsung 970 EVO Plus M.2 | Win10 Pro 64bit
Saw some Pimax engineer comment at the forum that some future Pitool version will feature a slider for the GPU utilization to tackle this problem so they are aware of the issue and it exists and how to fix it.
@SweViver Weird that even Sweviver is still playing dumb as of this real problem even existing…
Just hope this problem will be finally fixed for us with these handicapped 5K+ versions suffering from this and still having to roll back to the version .144 of Pitool for over a half a year now (the stutter problem is seen in all Pitool versions after .144 currently).
Virtually lost all confidence in Pimax to get rid of this. In my right mind I would not ever consider ordering another product from this company as the support for their products is this poor. 
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I think you may have part of the answer to your curiosity.
If SweViver had the issue on a serial that does not match your model. Then the natural conclusion is that those who have it might not have completed a clean install as it cleared his Judder on the 5k+. Your also presuming SweViver is aware of any & all developments.
So like Pitool 244 had a compatibility issue with Ser 204 it is possible as you said this Judder might be more limited to 202.
If you haven’t please fill out a Bug Report in Pitool\Report Bugs “Judder” topic. As this can help compare user setups to see if Serial 202 is a commonality.
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Might be worth a try for those experiencing judder as that’s basically been confirmed here:
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I know this problem exists, and I also know I had this problem myself. What I suspect though is that it has nothing to do with a specific 5K+ model, as I had the same issue with two 8K+, the old 8K and two 5K+ this late summer.
This problem IS a Pimax problem for sure, but it seems more to be a driver/software conflict rather than hardware related. Many ppl had stutter/judder issues when running RGB light controller software (especially MSI and Corsair). Turn the software off and problem is gone. Have you tried that?
For many others, this was just PiTool/SteamVR related. Clean up all PiTool files, reinstall SteamVR and problem gone. Again, did you try that?
Also, make sure to have correct RAM timings. My Corsair (same as yours) 4000Mhz sticks initially gave me problems with occasional/random stutters/judder even in pancake games until I downclocked them to 3600 and found the correct timings.
Why versions above 144 only gives you this issue is for me unknown, but I would suggest you to try your 5K+ on any other PC/laptop with the latest PiTool, at least so you know if its your current configuration that is the problem or not.
Also, does the stutters/judder occur in 64/72Hz mode as well or only in 90Hz?
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Am I only one suffering FoV fixed to small every time I boot my PC? Even if I change it to some other FoV , apply, and save it, small FoV pops up again after next booting.
One more thing, I see very thin, dark blue chromatic aberration on very edge of the displaying panel with small and potato FoV. Large or normal FoV do not show me something like that.
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Do you have 120Hz as default?
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Nope. 90hz default. 2020
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Thank you SweViver for the prompt reply 
@Heliosurge I have now made a bug report as you suggested: https://community.openmr.ai/t/video-judder-studder-dec-2019/24537/6
As I wrote in the bug report, I’m not using any RGP control software, running all hardware without any OC, always using the latest NVIDIA drivers and Windows updates. Did a clean install of Pitool (uninstalled old version, rebooted, deleted Pimax folders under C:\Users\user\AppData\Local, LocalLow, Roaming and C:\ProgramData, and installed new version).
Tested on all available refresh modes (currently no 120Hz available for us 5K+ S/N 202* owners 
) and still getting these stutters. I do not have any other PC capable of running the VR headset to compare but I think it would be irrelevant anyway. Everything is ok after rolling back to Pitool version 144. Alex Liu is acknowledging this issue and commenting it being resolved with a GPU utilization slider in future Pitool version here: https://community.openmr.ai/t/video-judder-studder-dec-2019/24537/3
@SweViver Martin, please put pressure to the Pitool developer team to get this GPU utilization slider in the software as soon as possible as we who have been suffering from this stutter problem have not been able to use the latest Pitool versions for over a half a year now because of this issue.
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Well I am sure you noticed more than just serial 202. 
The Reporting Sub there will help pimax have a clean area on the forum to review member’s reported issues free of clutter replies. As seen Alex is on top of this issue & has replied. They already implemented a quick release to fix Serial 204 which seemed to have a compatibility issue with pitool 244 resulting in 249 being released.
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Im also seeing alot of extra sharpness which results in a lot of aliased lines and moire patterns. Can anyone confirm this?
5k plus 1080TI
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I’m not seeing that on my 8K, although I thought the contrast was a bit better and found small text to be more readable. According to the release notes, the backlight brightness setting is currently ignored, which might explain the contrast improvement I noticed (since I keep the backlight brightness on dim). Also, I noticed that the blackness of space seemed a bit grayish, but I assumed it was some local gas clouds (and could well have been due to the background brightness setting not been set to Dim).
Do you think increased contrast actually be what you’re noticing?
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I am having the same shutter annoying problem. 5k+ here
Even with a brand new PC i get jutters, so it is not from old pitool installations though that may have caused something else on your end. I have two pcs, a mini itx with a GTX 1080 and ryzen 1600, and a rig with a 2070 super and a ryzen 3600 both with 16 GB of ram.
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