Mr.uu´s 8kX Experiences

Today i have some spare time to try some games and find good settings for my 8kX.

I selected HL Alyx because it is one of the best VR games out there.

I run a i7-7700k @ 4.8GHz and a 2080ti @2000MHz for reference.

Before i run the game i did add “-console -vconsole +sc_no_cull 1 +vr_multiview_instancing 0” to the start options of the steam game. I let the game do its performance adoptionmagic.

Pitools is at 1.0, pp and smsm off, FOV small.

Started the game and centered the hmd on my so i saw a crisp picture.
Went to the ingame options and did select the ultra settings.
Did start a new game and found myself at the balcony of chapter one.
looked around and did realise to see some aliasing (on the cables left above the black combine outpost, going from there to the center citadell). started fpsvr and saw that steamvrss-setting was at 40% (below 2000v pixels). Frametimes were way below the critical number.
Walked around and was nevertheless pleased by the sharpness of the textures, reaching to the house on the other side of the street.
Decided to bring up the steamvr menu, set the steamvrss value to 80% (around 2800v pixels), closed the game and restarted it.
This time i immediately got the message that the settings are probably to high to have a nice experience. nevertheless i started the game and was back at the balcony, now with frametimes close to the critical value, sometimes (very rarely) spiking above it. Aliasing was almost none to see anymore. Could not make out a big diference on close items, but looking from the balcony down to the other houses, i could see details of the rooftop now as far as the end of the street.
Realised that something looked odd with volumetric fog. Closed one eye and saw that there is a difference in the picture rendered for each eye. Either because of pp off or it is not rendered at all in one eye. was hard to tell. Decided to change steamvrss value to 60% (around 2400v pixels), set the pitools fov to normal and turn off volumetric fog rendering with adding the line “+vr_enable_volume_fog 0” to the start parameters.

jumped into forum to write this down. i will continue with edits.

Let me know what you want me to test for.

EDIT: let´s go on.

did a hmd restart to properly change to normal fov. started HL Alyx again with normal fov and again i got the message about the performance. checked steamvrss - was set to 80%. looked around, saw some minor aliasing. started fpsvr abd that showed me a ss value of 64%? hmm. looked around and enjoyed the benefit of the larger fov. but saw also the downsides. performance was not much less, probably thanks to HL automatic settings magic.

saw a pop in/out of shadows on the very right end (around 1cm in) of the view. This is probably fixable with a culling setting out of the starvr-thread (+r_size_cull_threshold_shadow 10)?

then i checked for the missing volumetric fog. and it was missing :crazy_face: but i did not miss it really. some dust particles still floating around, so to turn the fog of seems not a big deal. Maybe a different story for later in the game where there is lots of plant exhaust?

Then i checked for distortion at an open door and there was obviously a barrel distorton going on when turning. i brought up the steamvr menu and the desktop view, went into pitools and played with the screen vertical offset values - on the fly. love that feature! after trying different values and convinced myself to see improvement, i set it back to zero and pressed the hmd to my face as hard as possible. Distortion was gone! So with the screen offset values i just did move the center of the distortion up or down. the reason for it was my in deep sockets sitting eyeballs. sh*t.
Nevermind. i am not really sensitive to distortion, i adopt quickly to it to a point where it does not disturb me at all. lucky me. Left the vertical offset to -2/-2 to help in adjusting the hmd easier to my face and because it somehow looked the best with least and even distortion.

I did realize with all that fiddeling around, that the sweetspot (the area where you see clearly) is actually narrow. I have to undust my index again to doublecheck that. I think i remember the index having a better sweetspot and more clarity fov range.

Checked the steamvr ss settings and it really was set to 64% (2528v pixels). left it for good but maybe i increase it because frametimes performance was not close to the limit.

One more thing about distortions. I will go back to using small fov. mainly because i want to improve resolution (details, i want to see if i can achieve the 3160v pixels needed for distortion profile sweviver was talking about) and do not care so much about the outer (anyway blurry) extra fov area. and with the bigger fov the distortion gets more obvious. also there is a compressing of the image in this outer fov area. Even if i press the hmd fully ontu my face to get rid of the barrel distortion. surely something that can and must be improved in altering the distortion profile on pimax side.

now that @NextGenVR requested a lot of testing i hope to be able to give you results soon. :crazy_face:

Edit3: just a quick update.
i tried getting rid of the shadow pop-in on the very right side with testing the start parameter “r_size_cull_threshold_shadow” with the numbers 10,20 and then 50. No difference. seems not to work.


Have you activated Windows 10 v2004’s new GPU acceleration so that you can use Pitool’s Catalyst without stuttering? To get a high GPU utilization.


Is the overall image quality that much more impressive than the 5K+…does it feel like a big step up in visuals, clarity etc?


No. according to gamers nexus video it is of no benefit right now. And the 2004 is not rolledout yet in german.


yep. so much better.


I have it already, you can get it by forcing it. Just FYI if your GPU utilization is low, that may be the solution.

Thanks for the post. Looking forward to more of your opinions. I know you have said the visuals compared to the 5K+ are so much better. It may be hard to describe without A/B hot swap comparison. Is it possible to try to describe some more of what makes it way better? I myself find the 5K+ pretty good but have nothing better to compare it to. Compared to vive the 5k+ FOV reduced SDE and crispness of the image provides a greater “presence” to the experience.


Please try the climb with your 8k X :slight_smile:

Now that you have experienced HL-Alyx with 8K X and 75Hz, how did you feel the motion was, the feel of it all when loading guns and doing fast movement ?


For me hl alyx isnt even enjoyable with 90 hz lol ( I only play it with 144hz )

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Hey, thanks for testing out the tweak! Yes the volume fog issue is due to not using PP. I also sometimes get a GPU low memory error at the main menu of Alyx on my StarVR. Probably due to the tweaks.

Try again on Large FOV. To optimize performance, disable motion smoothing in SteamVR, set SteamVR render resolution to 100%, then go to Graphics settings in Alyx and Set Characters → Low (has nothing to do with character detail apparently), Shadows → Medium or High, Fog → Low or Medium.


As for some of the shadows being culled at the very periphery on the right, yes that is due to not using PP. I didn’t figure out how to get rid of that, but because it happened so infrequently on my StarVR One, I forgot it’s there. The console commands got rid of like 95% of the rendering issues and that’s good enough for me. There is some kind of shadow cull threshold you can look into, however, when I had tried them I saw no difference in game, as if the commands were having no effect.

After doing all of that and trying it out,
Can you do the following test for me?
Using the same launch options as before, add the following to it:

+vr_perf_hud 1 +vr_fidelity_level_auto 0 +vr_fidelity_level 3

And then re-enable motion smoothing. This will open up performance display on your VR headset, disable auto resolution and force it to Level 3 (100%).

Walk around in a large map in Alyx and take note of the values displayed in performance HUD and on fpsvr. Perhaps take screenshots.

Now exit the game. This time, remove the sc_no_cull, vr_multiview_instancing, and keep everything else as it is. Now go into Pitool on Large FOV and turn Parallel Projection (PP) on. Walk around in the exact same map as before in the same spots. Take note of performance HUD values as well as fpsvr stats.

That will let us know for sure whether performance is better with PP or without PP but with the launch options.


The big deal for me is the increase in sharpness. imagine the pixel of the 5k+ around 2/3rd of the size and the fixel fill per pixel not visible and between pixels barely visible.


That sounds promising! You probably got the thick foam like the other people who already got their 8kX?
Your experiment indicates that the thinner foam might help then in your case!

Does anybody know whether we will still get the thinner foam? In the Pimax NOW event it sounded as if it were included?


something that is on my list. but i have only the Oculus version. Need to install Oculus and all the sh*t software. But i will eventually buy Lone Echo anyways. So will do that. But later on.


did just run around in first chapter so far. need to load another chapter for intense ingame shooting :stuck_out_tongue:
So far the experience of 75Hz is completely flicker free. but i am probably on the not so sensitive side, played my 8k mainly in 64Hz (but i saw the flicker there, but acceptable) and use my Quest without seeing flicker.


I challenge you to be more specific :wink: Drill down to the core aspects of the visuals that make it stand out over the 5K+. I’m interested in your own specific impressions over generalisations.

After having tested the 8kX - would you (if you weren’t a backer) now buy the 8kX bundle for $1800 in case you wouldn’t already have it?

honestly spoken, i was very shocked about the distortion at first testing my 8kx (it came with the thick facefoam which has the cutouts for the glasses). Then i swapped the thick foam with the one i had on my 5k+ (much thinner. maybe half as thick?) And the experience was immediately much better.

I hope i receive the thinner foam with my eye-tracking pack. I should tell pimax that asap.


@mixedrealityTV - I know people have asked this already. Did you have time to retest the 8kX with a thinner foam? Seems to make the world of a difference for some people. After your anniversary holidays that is :slight_smile:


i doubt that that makes really sense. because we are all individuals. I see no benefit in loosing myself in the details and having to “hotswap” my 8kX with my 5k+ or 8k just to give you impressions that are of course VERY subjective.

I try to focus on the things that will most of the users experience, too. I think thats the right approach.