How critical are VR fps requirements?

forteh · 23 Jan 2019 at 10:05

Wishing to pick the collective brains here

Picked up a DK2 in mint condition for 75 quid over christmas as a quick and dirty way to try out vr, figured if it's a bit crap it's not the end of the world (I won money in the solidworks2019 beta test bug hunting competition so not out of pocket either way). I fitted a matte screen protector with pretty much eliminated all screen door effect (looks like it's got a very soft blur filter on it now) and generally it's all working as intended using the latest oculus drivers. Can't adjust the ipd but by happy coincidence mine is 64mm which is bang on for the dk2.

My machine is below spec (officially), it's a [email protected] with an evga gtx780sc so I get all the warnings in oculus dashboard but plays most things quite happily with no judder for the most part. Fallout4 struggles a bit (using vorpx) but I think I prefer it maxed out @1080 than in lower quality 3D but elite and alien isolation run really smoothly.

In elite, I have everything on ultra, sampling at 0.85 and and hmd supersampling at 2x and it's all sharp, looks great and is perfectly smooth, framerate on the monitor is around 50-70fps dropping to 30ish in stations.

Now how critical is it that you hit the refresh rate? The DK2 is 75hz so by all accounts I should be getting motion sickness and generally not be particularly comfortable, but I'm not, I can quite happily sit there for three hours nonstop (by which time I have to wake up in 5 hours time

). Am I just lucky and not affected by low framerate VR or is there something else going on? Any thoughts?

Overall it's awesome and perhaps the best £76.89 (£1.89 for a pack of 5 screen protectors) that I've spent on my pc

Ravenger · 23 Jan 2019 at 10:18

A consistent framerate is what's required. If you get judder or a highly variable framerate it can cause motion sickness.

The Oculus Go is 60hz (though can do 72hz) and that works fine, if a little flickery on some games.

forteh · 23 Jan 2019 at 11:06

Ah that makes sense, it is a pretty stable framerate albeit slightly below refresh rate. The only time I can tell if it's dropped is when quickly panning my head it occasionaly flashes up a black screen in the direction I'm panning as the gpu loads the frame up, still super smooth though.

I can't compare it to any of the consumer HMDs though but I'm super happy with it for what I use it for (seated only gaming, sims and always with hotas/steering wheel so controls aren't an issue.

deuse · 23 Jan 2019 at 14:26

My Vive is 90Hz and it never goes below that now. On my old rig it did go below and it looked crap.

Ravenger · 23 Jan 2019 at 14:46

Both Rift and Steam VR also have software techniques to smooth out the framerate if it goes below 90fps, locking to 45fps and interpolating the frames. However this can result in visual artefacts.

forteh · 23 Jan 2019 at 15:35

I don't get ASW triggering and locking it to 45fps, I'm not sure if the DK2 supports it now but it should lock to 37.5fps I believe? The fps (as displayed by steam on the monitor) happily sits below the refresh rate but isn't locked and doesn't display artifacts or look any worse. I would say it's still playable down to 30 fps although obviously higher is a little smoother, perhaps after years of arma3 I see 45-50fps as perfectly smooth

I installed the oculus tray tool last night so I'll play around with the ASW settings on the game profiles and see if it does anything.

Zeeflyboy · 23 Jan 2019 at 21:48

Ravenger said:
Both Rift and Steam VR also have software techniques to smooth out the framerate if it goes below 90fps, locking to 45fps and interpolating the frames. However this can result in visual artefacts.

looking forward to ASW2.0 - should greatly reduce those artefacts. https://uploadvr.com/asw-2-oculus-medium-changelog/

GBRusty · 24 Jan 2019 at 08:35

@forteh It does sound like you've got a lucky brain and not susceptible to VR sickness

It's a good trait to have. I can't remember much back to my DK2 days but sounds like you're having great fun with it.

I wonder if I'd like the reduced resolution having now got used to the Vive? It's probably like upgrading a monitor. You're perfectly happy with what you've got but once you've tried an increased res you'd find it hard to go back.

I also vaguely remember that the oculus had excellent ASW which will definitely help

Once you win another competition you can put that towards a newer headset

forteh · 26 Jan 2019 at 13:42

I'm not sure that I'm completely immune as fallout 4 via vorpx in third person at 21fps is positively vomit inducing as you pan around

Fiddling with elite's settings last night, I've dropped texture level down to high (from ultra with 3gb haha) turned dof off and environments down to high from ultra, aa to fxaa and turned supersampling from 0.85 to 1.0 with hmd sampling turned up to 2.0. I'm still pulling 60 to 75fps in open space, dropping to 37 at stations/planets (asw is kicking in, I just hadn't noticed!) and it's pin sharp with no screen door

I dare say that if I were to try a cv1 I might then hate the lower resolution, I would need an entire machine upgrade though which I can't afford. I have been looking at picking up a cheap 1060 or 580 but I can't really justify it immediately given that the performance from the 780 is pretty good for now.

I think I'll look into overclocking the 780 and see if I can eke out another 5-10 frames. Will have to put the evga acx cooler back on it though, it's currently passively cooled with a thermalright gtx285 cooler, it's silent but doesn't allow any headroom for overclocking as it throttles because of hitting the temperature target sooner.

aoaaron · 29 Jan 2019 at 07:38

if you have an oculus rift just tick ASW all the time and aim to hit 45fps.

GBRusty · 29 Jan 2019 at 07:48

Just had to look up the dk2 refresh rate. Max is 75 so would ASW do 50% of that or still try for 45?

forteh · 13 Feb 2019 at 20:54

Well overclocking the gtx780 gave a small performance boost but it was hellishly hot and noisy, my machine is all but silent and caseless.

Trawled around the various second hand procurement locations for gtx1060s and rx580s and the going rate seems to be around 140 quid. Although both are quicker than the 780, it's not a huge jump and more of a sidegrade.

Eventually came across a bunch of asus rog strix 1070s from a decommissioned mining rig for 200 each, had to collect from St Albans but happened to be passing for work so grabbed one.

Elite is now running a combination of high and ultra with supersampling at 1 and hmd quality at 2, never drops below the 37fps set by ASW and I find that perfectly acceptable. Best bit is that the card never gets above 57°c and is virtually silent

Happy with the card, should help drive the oculus in newer games a little better as well, fallout 4 murdered the 780

SupraWez · 1 Mar 2019 at 10:43

forteh said:
In elite, I have everything on ultra, sampling at 0.85 and and hmd supersampling at 2x and it's all sharp, looks great and is perfectly smooth, framerate on the monitor is around 50-70fps dropping to 30ish in stations.

Two lots of SS?

If you are running two lots of SS it will be killing performance.

I don`t use any SS via in game settings and do all SS via the OculusDebugTool.