Renamed title: Using a 5k+ to mimic 8kx performance

I’m experimenting with performance vs resolution with my 5k+. With Pitool Render Quality at 1.0 and FOV on Large, when I adjust the SteamVR resolution slider to 1440v it gives 2336 for horizontal. Why not 2560 for horizontal? Hidden Area Mask makes no difference, checked or unchecked it’s always 2336 x 1440.

FW 255
Pitool 253

Just to be sure, I always restart Pitool and SteamVR after every change.

the horizontal view is not fully utilized because there need to be space to move the picture on the panel to match the physical ipd setting of the lenses.

at least that would be my assumption.


OK thanks. I figured there must be some reason but couldn’t figure out what. And I guess it’s normal for Hidden Area Mask to have no effect? Man what a saving that is, like 25% fewer horizontal pixels rendered!

What do you mean it has no effect?

Looking at the resolutions displayed in SteamVR, when I change HAM from checked to unchecked the numbers don’t change.

Apologies for my confusing comment on 25% fewer horizontal pixels, that was in reference to changing from large to normal FOV. Should have stated that.

Sorry also for slow replies, I’m in and out as I pursue weekend chores.

HAM does not change the resolution, it is applied over it to mask the area which fits into the rendered rectangle, but is not visible because of the other reasons (lenses, design, etc.). So technically it just mask the area you should not see anyway for the GPU so it does not render uselessly in it. Therefore turning it on or off should not be visible.

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Thanks guys for the explanations. I’ll carry on with my performance checks knowing all is as it should be.

Hmmm… new question though…

If the 5k+ only renders a max of 2336 horizontally per eye instead of the native panel count what is the maximum horizontal for the 8kx? Same ratio?

So .9125 x 3480=3504 max 8kx horizontal?

More specifically, what is the horizontal pixel count in normal FOV for the 8kx? Trying to get a feel for how my system could handle an 8kx. Large FOV will bring it to its knees for sure so being more realistic I only need to explore normal FOV.

Using an 5k+ to match expected 8kx performance load, I think the following will apply. There are two “ifs” but I expect they are true.

IF the ratio of the 8kx’s reduced horizontal pixel count (for IPD adjustment) to the total panel horizontal pixel count is the same as the 5k+ ratio, i.e., .9125, (deduced from SteamVR resolution per eye readout)

AND the 8kx Normal FOV horizontal pixel count is 75% of the Large FOV horizontal pixel count as it is with the 5k+, (deduced from SteamVR resolution per eye readout)

THEN the following calculations apply:

3840 x 2160 x 2 = 16.5mil – 8kx native panel
3504 x 2160 x 2 = 15.1mil – actual max Large FOV resolution (.9125 horz reduction for IPD adjustment)
2628 x 2160 x 2 = 11.3mil – .75 Large to Normal horizontal reduction
3285 x 2700 x 2 = 17.7mil – 1.25 SS (as Mirage335 suggests in one of his videos)

So running a 5k+ or 8k at 17.7mil total pixel count should be a good representation of an 8kx in Normal FOV with 1.25 SS.

Do I have this right? Have I missed something?

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No idea, but your calculations look reasonable.

Unfortunately, I have to use PP for my favorite game (Elite D) and I cannot keep a decent framerate at that res on my (quite good) system. I’m using Pimax Quality of 1.0 and SteamVR at 50% with Normal FOV, for a res of 1564 x 1468.

My system consists of an i7-8700K, 32GB of DDR4 3600 ram, and a factory-oc’ed RTX 2080. It looks like i’ll be running at a suboptimal resolution, until I can get a 3080 Ti. Still, I’m sure my future 8KX will look better than my current 8K.

Whew, i did not realize you were running with such a low resolution, sure effects and all are nice in Elite but when i was playing would personally turn those down a bit for a gain in visual clarity due to a higher rendered resolution, i think aliasing is more of a detriment than somewhat lower settings.


This does not sound right. On my Ryzen 5 2600X with 1080Ti I was able to get an acceptable framerate (60-70 in free space) with twice the res you have (roughly 3800 x 3200, which corresponded to PiTool RQ=1.0 and Steam SS=100%). (It was on an ancient PiTool v132.)


It looks sound to me. If you match the FOV configuration (i.e. Normal, with Normal, PP with PP) then you should experience the same aspect ratio (or very similar) since the lenses did not change between 5k+ and 8k-x, so the question is really only the right pixel count, to simulate the 8k-x rasterization load (as the geometry load, because of the same FOV, should be the same).

I cannot comment on the recommended values by @mirage335 as I have not seen 8k-x yet, from 5k+ perspective it seems a bit low (as I was usually running 5k+ at the similar res in Native mode), but the chances are 8k-x can compensate for oversampling by higher native pixel density.

My reaction as well, ive got an i5-4690@4.5gz + a regular 1080 and i quite comfortably run a resolution of 2200ish (pitool 1 and steam 70%) without much issue with medium and some high settings in Elite.

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Sorry Neal, gotta agree with these guys. Currently running 3080 x 2632 with most settings on Ultra for a solid 45 FPS with Motion Smoothing (I know you don’t like MS). Your overclocked 2080 should get close though. The good news is that you can definitely get better results straight away :+1:

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Thanks, I appreciate your looking this over. For me this calculation is very encouraging because I can run my favorite game (rFactor2 racing sim) at 18mil pixel count and maintain 64fps with a fair amount of game detail and 15-20 opponent cars on the track. It varies some with car and track choice but in general it’s very achievable.

A concern for me is whether or not the 8kx supports 64fps. It should since it is so taxing on most systems.

Edit: I’m seeing Mirage335 report using the 8kx in 60hz mode so yippeee! :grinning:

Personally, I like having my graphics options set to high or ultra. Also, I have an 8K. If I increase the res too far, I start seeing color fringing (due to the 8K’s “rainbow” subpixel arrangement).

Do you have Smart Smoothing ON or have lower graphics options in ED? I find SS to be highly annoying, so I leave it off. I don’t like FFR Conservative either, but I sometimes enable it to improve the framerate.

I’ve tuned my settings so that I get 50+ fps inside stations (and 80 fps in deep space).

So neither in-game supersampling, nor HMD Quality, above x1.0, either?

chances are 8k-x can compensate for oversampling by higher native pixel density

Incredibly so. Recent experiments with VorpX are incredibly sharp - outright as good as a 4k monitor with the compositor pipeline at native resolution (Render Quality 1.0, vertical pixels at 2700 with Parallel Projections).

Slightly offtopic - there is now a slim chance Star Citizen might work acceptably well through VorpX with the 8kX. However, I am not in a hurry to put my time into hacking around what should have been a native VR experience to begin with.

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I am also curious about using my 8kx with vorpx (love it). And the fact that pp does not negatively impact performance with vorpx so much because only the composer uses the blown up resolution (words from ralf himself) makes me giggle like a small kid when thinking about all the games i will play with it in fake- or g3d. Just bad that vorpx loves high refresh rates (if smartsync for a steady experience is on and cuts the framerate in half) and therefore i love to use it in 120Hz on my index …