First of all apologies for taking a while to get this into a post — Though things been hectic here with the lockdown in " City 17 ". Having received the " 8k x " a few weeks ago I also wanted to get a feel for the headset over an extended period. Trying out a range of software and making a direct A - B comparison with the Valve " Index " and Pimax " 5k + " headsets at hand. I still feel I could do more testing and tweaking but hope this can be useful.
To give some context I'm a full - time creative technologist - xr developer and have worked with " Funktronic Labs " , " Mc Cann London " , " Smithsonian Freer - Sackler " , " Nasjonaalmuseet " and " Mona Museum " amongst others. I remember the MTBS forums and a young upstart hacking on the " Sony HMZ - T1 " complaining about the field of view ! That nascent community movement would eventually inspire me to pursue a stereo - rendered future in development.
— I have been involved in vr development since 2014 and own : DK1 / DK2 / Rift CV1 / Vive DK / Vive Pre / Vive Retail / Samsung Odyssey / Valve Index / Pimax 5k + / Pimax 8k x as well as a collection of some absolutely horrible and less horrible ar - mobile headsets. I have had hands on experience with the " Reverb G1 " and plan to pre order the " G2 " for development use. There seems to be quite a bias when we talk about Pimax and I felt it was important to cut through some of that crap , share first hand impressions from behind the lens , and perhaps give some perspective as to why resolution still matters a great deal.
# 27th September 2017 ( 4.24 pm )
Three years is a long time no doubt. Its about the amount of time a human baby learns how to speak from imitation and I remember backing the Pimax " 8k x " as a moon shot from a largely unknown , and unproven company. Though I do remember at the time trying to put together 3d showrooms and architectural walk throughs in " Unreal 4.10 " and feeling utterly dismayed by the lack of acuity and resolution in the " Vive Pre " development kits we had at the time.
The feeling of " presence " was definitely there but something essential was still missing. To be precise it was peering through small field of view displays hampered by poor SDE , at worlds filtered through low resolution. Its been slow going since re : functional improvements to HMD image quality with both Facebook and Google ditching higher end headsets for Snapdragon 821 / 835 and hitching their vision to mass market adoption rather than pushing the actual quality of the experience.
— So higher resolutions and better panels : Were kind of relegated to enterprise headsets like " Varjo " , " Star VR " , " XTAL " and priced accordingly , out of the budget of most enthusiasts. I'd still love to try out the " VR - 1 " and pass through but perhaps will end up building that onto the Pimax " 8k x ". These were dark days for those of us who had been dreaming of better resolution or more capable hardware.
In the meantime I also received the " 5k + " loaner from Pimax and that was a statement of intent. I was unsure about it at first , but gradually won over by its light weight design and increased resolving power. That was enjoyable to use for development in the studio with existing lighthouse tracking and controllers. The addition of 120 Hz / 144 Hz modes later was a nice bonus as well ! I still love this headset due to the weight and comfort ( at 586 gm ) that puts it close to the " Rift ". That was superceded in the studio with an upgrade to light house 2.0 , " Index " - with knuckles and now the Pimax " 8k x ". How did it fare ?
# Shanghai surprise
I never put much truck into Pimax dates and schedules so never got obsessed with the delays this headset had. Though it was nice to receive a double boxed package with the " 8k x " inside. The headset and cables come packed into a matte black box with a handle similar to the " Rift " deluxe case. I guess you could call it " premium cardboard " if you're into that sort of thing. There's lots of padding inside which makes it useful for storage or transport. It'd be great if somebody could design a box that could turn into a headset stand using the packing materials.
Fig 1. Pimax unboxing - backer card
First thing is a nice letter from the Pimax founder : Robin Weng and unlike the oculus " kickstarter " thanks card - its actually hand signed , and not printed which adds a bit of class. The " 8k x " backers also receive personalised support from a representative there. It was a surprise anyhow to get a phone call from china one night to enquire " how I liked touching the headset ". Maybe a bit of a personal question but appreciated nonetheless. They also wanted to make sure I was up and running ok.
— Though by that point : I had already run into and found work arounds for some of the initial set up issues. [ 1 ] The first was USB related and simply having to turn off power saving in the root hub. To get around errors complaining about " not enough power draw " through using just the display port. The cabling is comprised of 2 x USB 3 plus 1 x Display Port 1.4 connection wound into a single cable. I'm not a fan of the tension here but it seems to be working itself out over time.
[ 2 ] The second issue was losing headset tracking on reboot and subsequent sessions. Though managed to get the USB output recognised switching USB 3.x ports around. Basically unplugging and then plugging , to get the devices recognised again. Once thats done you can see that one of the USB cables runs audio to the " C-Media " DAC on board. The other meanwhile carries the positional data for the headset and controllers.
So not quite a frictionless set up ? I do however remember the original " Vive " developer kits and hunting around - having to blind delete usb devices in " usb deview " for wands and blue tooth pairing to be recognised. For each and every new session. The Pimax " 8k x " is a walk in the park compared to that and a little persistence goes a long way with most hardware issues. Jump cut to this photo of Robert Pirsig on his Honda CB77
for handy reference.
Fig 2. Pimax \" 8k x \" top down
# Physical " 8k x " headset
The actual finished production " 8k x " headset takes a lot from the " Vive Pro " playbook in terms of its styling and colour. Though its not one with many wins , and where the black casing of the " 5k + " was minimal and sleek the " 8k x " takes a more corporate turn with a business blue - and silver paint on plastic scheme that comes off looking a bit cheap. Picking it up it feels substantial , and on first inspection the foam - plus side plastic panels are generous and adequate but not premium.
Its a step down from the " Index " facial interface and finish in terms of the overall build quality but solid and with no creaks or looseness in use. I'm running the standard foam and not the " comfort kit " and was supplied a matte black " silicone protective cover " which is bad ass. Putting the spiked cover on does add another 116 gm to the overall weight. Though how could you not ?
Fig 3. Pimax \" 8k x \" in night mode
— Thanks for whoever designed this : It makes up and does a great job of covering the faux " corporate " look of the " 8k x ". Its a strange but inspired move that transforms the headset into its alter ego that likes to stay on all night and get fucked up. The cover is also serves a practical use in helping to absorb contact impacts with putting down - picking up the headset during development.
From a subjective standpoint the weight feels about the same as the " Index ". The now familiar screw - in mechanism from " PS VR " is also present and helps to clamp your head in. I recall a distinct sense of my eyes being a lot closer to the lens ! Though transitioning from the " Index " might have something to do with that. I later measured the actual weight of the " 5K + " and " 8k x " for comparison and will add that as an appendix.
Fig 4. Oculus Rift at 490 gm
For now the best description is that the " 8k x " is heavier though with more even weight distribution across the head than " 5k + " due to the semi rigid , plastic frame. The 4k panels still mean that most of the weight is at the front and you really need to find the balance between a tighter fit that feels more secure. Being careful not to put too much of the weight on your cheekbones either. For the most part I was able to be in headset for hours without issue. Its easy to lose yourself in the 4k presentation and come out with panda face from the gasket.
There has been talk about the Pimax " canted displays " resulting in a lack of stereopsis for some people. I find this hard to believe as the " 8k x " contains a dual fresnel lens set up projecting the rays directly forwards into the " eye box ". For what its worth I have a fairly conventional face with two eyes , and a nose and having no such problems with depth perception. If you have not seen a Pimax in person their lens assemblies are huge and 2 - 3 times the size of other headsets. There is a massive sweet spot and detail remains sharp from center to the sides.
Fig. 5 Pimax \" 8k x \" lens , interface - and clamp
Another nice quality of life improvement has been the removal of the external 12V / 2.0A supply that the " 5k + " required. All the power to drive the displays now runs through the sleeved headset cable though as mentioned previously there is some tension there. Pimax comes with a 5 m tether and an extra 1 - 2 m would have been perfect ! I guess we need to wait for the 10 m active - fibre optic display port extension that is in development.
Flashing the stock firmware to latest [ 22.214.171.1240 ] was trivial and pairing the " Index " knuckles controllers has been quick and reliable without a hitch. Even swapping between three headsets the blue tooth worked great. Pairing controllers was painless and worked each time as expected so something has improved here. I dial in a measured IPD of 62.5 mm from the " eye measure " app. That uses " ar kit " front facing lidar , to get the distance between left - right eye transforms. Followed by a visual check in headset and we're good to go !
# Visual impressions
I spent more than 70 % of my time in " Half Life : Alyx " putting the " 8k x " and other headsets through an A - B comparison. I'll go through some of the observations from that later but the initial impression is immediate - and the sense of visual detail from the 3840 px panel is stunning ! The fortuitous inclusion of RGB stripe works in tandem to create a consistent - flawless image where the " visual noise " familiar from other headsets is gone , simply resolved out of existence.
This translates as a feeling that the scene is more " relaxed " in its presentation. The " screen door " is just not there any more and I haven't been able to see it. That in turn means you can focus and resolve objects at farther distances. The extra resolution is a presence multiplier in that visual and spatial cues like lines of perspective or convergence are enhanced. Not to mention the tremendous effect on the appearance of surface materials - the substance of virtual worlds in headset.
Fig 6. \" Half - Life : Alyx \" native 4k
It's all running at 75 Hz in native 4K with no upscaling and this makes a tremendous difference. The " 8k x " does have a 2160 px upscaled mode that can run at 118 Hz though the full consummation of what these panels can do its " native mode " all the way baby ! The clarity these extra pixels provide along with their CLPL low persistence provides a front seat to the spectacle. I am guessing that is some kind of blinking LED back light and running " 8k x " in normal 140 ° mode with no motion interpolation , brightness - contrast both at zero.
Its noticeable booting up from the initial " Valve " logo how the colour - and resolution are resolved in amongst the specular detail of the highlights here. The intense crimson lettering seems correct and doesn't bleed , remains defined at the edges between high contrast colour blocks. Then into the " start menu " which is normally aliasing soup - this time rendered in clean lines. I notice new details on the knuckles controller models and all the text looks spot on.
# The material world
Turns out the first 10 - minutes of " Half Life : Alyx " make a great test bed for headsets with the shifts in light and tone , from interiors to exteriors and props in between. The initial panorama looking out over the rooftops is an astounding moment in the " 8k x ". Its the moment you realise you can see out into the distance , and resolve a significant amount of detail that was previously obscured through the haze of staircasing and shimmer. Instead there's a clean resolution of the rooftops , their outlines and tile textures in the mid - far field that just hits you.
Much kudos to the technical artists who worked on " Half Life : Alyx " because its is food for these panels which rise to the occassion when presented with some well done 4k / 8k textures. The play of sunlight on the wooden table in the room with the camera and snark. The sheen of the varnish with its localised wear and grunge maps , to the hairline scratches on the controller in " Robot Repair " the " 8k x " just keeps on giving in terms of detail.
Its really beautiful ! and the " 8k x " is a maniac for good materials. I was initially running at render scale 1.x - but it was hard to resist pumping this up to 2.x , so it has stayed there since. This headset is all about that kind of madness. Though 1080 Ti temperature has been reasonable peaking at around 80 C so there is some headroom. I did end up needing to force native 4k output through command line options. Turning off the " Half Life : Alyx " dynamic scaling based on gpu hardware which would otherwise limit the output frame size.
Furthermore there was an issue with " contact shadows " being rendered only in the left eye , and prone to head motions. So I'll have to look into that some more. The distortion from the wide modes of the " 5k + " is in a practical sense gone from the " 8k x ". The best place to check is in the elevator that takes you down from the rooftop and parallel lines there.
Fig. 7 Pimax \" 5k + \" at 586 gm
In headset you can see there is more acute distortion of the image here. But its further out in the corners , no more than around 5 % of the image and you don't see it in normal use - unless rolling your eyes , and straining to look for it at those extremes. The whole thing with Pimax headsets and distortion seems to have taken on a mythical status when perhaps the issue comes from the ridiculous " large mode " in the first place.
There is still aliasing to be found with " 8k x " however its now isolated to edge cases with high contrast and high frequency detail. Such as the long horizontal pipes at the start or the tines of a silver fork " Russell's Lab " later on. Its now the exception rather than the norm and running at render scale 2.x does give a noticeable improvement. The reduction in all this noise results in a new found appreciation for the materiality of the 3d objects around you. I couldn't help but feel I was inside of a deluxe " artbook " remastered version of the game and its a treat.
# More inconsiderate rambling
So much so that its re - igniting the fun of vr again for the moment. The pure pleasure of diving back into " The Blu " which has always been a go to new headset experience. Just as with the bump in headset panel resolution from the original " Vive " , to the " Samsung Odyssey " and again to the " Reverb G1 " the " 8k x " reaches a new watermark in resolving detail here.
I always enjoy booting up " The Blu " and it has become somewhat of a benchmark - baptism. It's thrilling each time to see more details in these scenes , and with the " 8k x " it was no different. Each time returning to the bottom of the ocean , to sea what eyes could see : the outlines of the fishes in the far field with lighting filtering through them clear. The skin of a whale - barnacles , and growth visible , lit on finely delineated flippers whooshing past.
The jellyfish migration scene is even more beautiful - and a good test of the colour reproduction which I have no qualms with here. The colours are sharp , vibrant and saturated at these default settings. In fact over these three weeks I have not felt the need to tweak brightness - contrast at all. I'm seeing the angel fish move and dart with precision and clarity , due to the low persistence as well. The picture from the LCD is gorgeous and doesn't feel lacking in its presentation. With the final scene in the darkness showing no banding - neither crushing detail in the dark tones."
Fig 8. \" Aperture Robot Repair \" native 4k
Aperture Robot Repair " is also a show stopper in the " 8k x " and materials here are rendered with enough care to see micro surface details at play. It cannot be stressed how much the 3840 px resolution brings great " physically based " materials to life. Though as a side note : games with baked in textures , compressed shadow maps and other rendering short cuts do appear profoundly awful so the increased visual acuity can be a double - edged sword. But boy , does it slice and dice !
Motion in " 4D Toys " and " Virtual Virtual Reality " was smooth and colours saturated. I think even sparsely textured games can benefit from " 8k x " and its ability to make polygons great again. It just feels as though a lot of gunk has been " removed " and the display is unfettered. " Text Mesh Pro " looks incredible in headset. This goes back to that earlier thought of scaling with resolution. The " 8k x " can reach new heights but most content is not future - proofed against high resolution.
" Lone Echo " which I was looking forward to testing did not fare so well. The LOD system in the game doesn't present a clear image in the background. Furthermore , shadow maps are way too compressed with inconsistent textures of different dimensions. The " 8k x " lays bare all the details and is not a kind mistress to those who have been naughty , in being nice. Similarly " Felix & Paul " productions optimised for mobile 5K strip rendering do not hold up. However , the raw 3840 px capture from an " Insta One Pro 2 " at 120 Hz is an interesting proposition.
# Low persistence
" Super Hot " looks hot without being blown out. The clean image in the " 8k x " also gives a boost with sharper , more well - defined diagonals , overall the presentation is crisp. Though wish I could remove the overlaid screen space effect there. I had no issues with 75 Hz and did not practically notice the step down in any motion - or movement in games. For example " Dear Angelica " is wonderful and the animations are crisp , smooth and gorgeous to behold. The " 8k x " having no problem resolving 3d content that can scale with the extra resolution.
Fig .9 - Marc Ten Bosch \" 4D Toys \"
There's a spot in the laundry in " Half Life : Alyx " near the start with the drones flying past that makes a great test for pixel persistence. In both the " Index " and " 5k + " running at 120 - 144 Hz the movement here causes smearing in the display. Looking at that same scene in the " 8k x " things are just much more clear with the innards visible - and able to be focused. I like a good refresh rate - who doesn't ? Though there seems more to this argument with low persistence thrown into the mix.
There was one edge case in " Zen Blade " which seemed to show frame skipping at 75 Hz and put this down to the low refresh rate. Though on closer inspection there's no motion hitching - with the blade stationary , so keen to check that out more. Putting the " 8k x " into 118 Hz mode eliminated this problem. I did try out some driving games like " Assetto Corsa " which was silky smooth even at 280 km / h in the Ferrari 330 P4 on the " old Monza " circuit.
I had less persistence for " Dirt Rally 2 " and its frame pacing which gave me a head ache. There is something wrong there , and " Dirt Rally 1 " was the same for me on " Rift " re : simulator sickness. I wanted to try " Beat Saber " as well though I have the oculus store version. That seems to be crashing for me - once past some prolonged stutter and initial load in. This would be another good test of persistence and will try to get it running in the " 8k x " which others have done.
Photogrammetry looks great in the " 8k x " if the texture detail is there. I was not able to get some " Unreal " based apps such as " Vanishing of Ethan Carter " , " Nefertari " or " Lost " to run in " 8k x " directly through the Pi Tool launcher though that is more of an sdk - and build issue. The textures in " Google Earth " , " Destinations : Mars " , and " The Lab " photo domes unfortunately do not hold up. However it would be trivial to super scale the inputs. I tried " Welcome to Light Fields " as well which remains a great experience albeit with bitmaps discernible.
# 4k as a baseline
For compatibility with some games the " 8k x" offers a parallel projection mode. That reprojects the content onto a plane. I loathe using this mode - though its required for some of the older games and need to check the Pimax community lists for shared settings. The " 8k x " is not a consumer headset for this virtue alone , and " Index " is a better choice for the build. But for the enthusiasts and developers out there who are looking for improved resolution its here.
The materials in most existing vr games that I tried do not hold up in 4k. So there is that too - and for every " Half Life : Alyx " and " Aperture Robot Repair " there are hundreds of games on the store that will not look good. Thats not the fault of the " 8k x " per se but rather it represents a call to arms in terms of rendering and materials ? Its a pleasant surprise this runs in 4k stereo on the 1080 Ti , but perhaps that also speaks of the efficacy of the FOV - based culling and optimisations to the game " Valve " have implemented.
![img](y3lihznfbph51 "Fig .10 \" VR Museum \" , a - mighty aphrodite ! ")
The latest " Pi Tools " also features panel brightness - contrast slider settings that can be customised to alter the output ± 30 % as an unmeasured estimate. But for the most part I haven't felt a need to make any adjustments. The production of LCD displays in general has been undergoing fierce competition in the last few years. I think as backers we lucked - out with the timing for the delivery of the " 8k x " because the panel is a corker. I am looking forward to the " Reverb G2 " as well and feel that this needs to be the new baseline going forwards.
Native 2K / 4K with RGB stripe represents sufficient image quality to make experiences where " presence " is wildly enhanced. The extra peripheral vision is icing on the cake - and opens up a more relaxed presentation. Free from the morass of dithering - and visual noise that comes from not being able to resolve against lower resolutions. That feeling of edging towards clear 4k with " Index " and " G1 " sails over the waterfall with the " 8k x ". It is really a substantial improvement on any headset I have ever tried. Perhaps the closest being the JDI 600 - 1001 PPI ( Japan domestic only ) high resolution units.
I remember the oculus " crescent bay " prototype demos and developers were crying in the halls for that one. The " 8k x " is just as much a significant step and throwing down the gauntlet of high resolution 4k , with great colour reproduction and low persistence. Thanks to all the people who backed this moonshot ! The " 8k x " also brings a unique modular eco - system of hardware add ons and I hope to receive my Droolon F1 " eye tracking " unit soon. Nvidia " variable rate shading " offers the promise of going even higher in terms of image quality so will update then.
Things like " Flight Simulator " in native 4k will have to wait for the time being. Though a future upgrade to 3080 Ti also seems a promising proposition. Thats where I think the " Reverb G2 " will find a great use case. I just realised I have forgotten to mention the " SMAS audio " though that has been decent with similar sound quality as the " oculus go " embedded unit. It doesn't compare to the " Index " off - ear firing speakers. However its convenient and the localisation - direction sounds spacious beyond its means.
The logical next step for Pimax is to push the native 4k to 120 Hz - 144 Hz refresh rates. That may require moving over to " a display port " 2.0 connection. I do hope they continue to push in this area as the " 5k + " was pretty great with the improved motion updates. I don't feel like I have hit the motion threshold at 75 Hz though " Beat Saber " might prove otherwise. I'm just glad that through the shambles of " kickstarter " there remained this other universe where Pimax have pursued image quality over a mobile form factor.
The dream of Iribe , had he got to build it and the " Google ATR " team , had they got to build it. Its evident spending some time in the " 8k x " that Michael Abrash and his requisites for virtual reality was a good path to be on. The increased field of view and acuity in 2K / 4K along with low persistence results in a feeling of immersion without distraction. The visual noise - so apparent in the important visual cues like edges and outlines finally rendered in an exact manner.
— CH 18 . 08
Ps. Shit ! The combine have spotted me ! I need to run out - but promise to attach the uncompressed screen caps from the " vr compositor " output. Thanks for reading and I'll update this post re : " eye tracking " unit once thats here too. Fuck , here they come.
[ Headset weight ]
Oculus Rift 490 gm Pimax 5K + 586 gm
Valve Index 765 gm Valve Index ( cushion ) 833 gm
Pimax 8k x 880 gm Pimax 8k x ( cover ) 996 gm
[ Test hardware ]
ASUS ROG " Zenith Extreme " X399 Socket TR4 ASUS ROG GTX 1080 Ti " Poseidon Platinum " 11 Gb ( stock air cooled ) Ryzen " Threadripper " 1950X / 3.4 - 3.7 GHz ( 16 - core ) G.Skill " Trident Z " 3200 MHz 32 Gb DDR4 ( dual channel ) CAS 14 - 14 - 14 - 32
— I have included some screen shots from what I assume to be coming from the " vr compositor " frame buffer output. The resolution seems correct though as noted both " Steam VR " and " Half Life : Alyx " have their own internal frame scaling. That overrides application of the " Pi Tool " render scale configuration. Forcing native 4k gave me a 7 % larger output frame without too much of a performance hit.
Please also note that its pointless uploading " through the lens " screen shots using " Imgur " as there is significant and noticeable compression there. " Image BB " is a better , lossless image upload service to use for comparison sake. The output from the vr compositor still needs to pass through the panel - lens , but it should give an idea of what native 4k does to resolve image detail :
[ VR compositor ]
Half - Life : Alyx
Aperture Robot Repair
Intervoke : Physiology of The Eye
— CH 22 . 08