Monitor vs VR performance

I did a small test today - screen vs VR (Oculus CV1), here it is:

Screen pixels total:

2560x1440 = 3 686 400 pixels

VR pixels total:

1080x1200x2x1.4 = 3 628 000 pixels

Oculus CV1 with 1.4 pixel density -i.e. roughly the same number

On screen I get 40% GPU usage with 60fps (vsync on)

With VR I get 70% GPU usage with fps locked on 45 only

It would be 70/45*60 = 93% for 60fps - more than double!

CPU is slacking in both cases; but yes with monitor much more…

scene is TF-51 - free flight Tbilisi

Is it normal or do I have something bad in my settings?

Entirely normal at this time...ED is working on a VR optimisation , but has hit a stumbling block , so -we'll see .

Well for VR ots rendering 2 scenes, one for each eye from a slightly different perspective.

There is a larger work load put on the CPU and GPU when rendering VR. Mainly as its two different screens with two different perspectives / aspects of view (to give you the 3D effect).

Besides the fact that there are two scenes to render, as there are two different viewpoints, setting PD to 1.4 increases the total number of pixels by 1.96, not just 1.4, as the oversampling is performed in both vertical and horizontal directions.

@Svsmokey - yes, we have to wait

...

setting PD to 1.4 increases the total number of pixels by 1.96, not just 1.4, as the oversampling is performed in both vertical and horizontal directions.

culpa mea, I test it with PD 1.2 next time ;-)

i have retested GPU load with PD 1.2

Screen pixels total:

2560x1440 = 3 686 400 pixels

VR pixels total with PD = 1.2:

1080x1200x2x1.2x1.2 = 3 732 480 pixels

On screen I get 40% GPU usage with 60fps (vsync on)

With VR I get 55% GPU usage with fps locked on 45 only

It would be 55/45*60 = 73% for 60fps - OK, it is not double but still too much I think;

hope the calculation is correct now

well, is it really so, that GPU is responsible for calculation objects positions?

I believed (probably worng) that it is CPU´s job and GPU just renders the scene, ie colors, shades, fading etc..

anyway, hope they find some improvements

;-)

Question is, how fast can your CPU render a scene? If it can do it in less than 11ms you can run at 90fps. If you're content with 60fps you have 17ms to work with.

My suspicion is your render time is more than 11 but less than 17ms. So when your rift defaults to 45fps your CPU and GPU have plenty of time to render the scene.

Either way it seems your GPU has plenty left to give. For VR you want your CPU render times down around 9ms or less on an empty map, which isn't dreadfully difficult but depending on your setup that's where I would look first

@Delta:

fps in VR is locked at 45 to compare GPU utilizationin in VR vs Screen

2D v 3D - no comparison.