Role of the CPU & GPU in VR simming

How to start… and not to mix everything together…

What is the role of the CPU specifically in VR? (I am not talking about CPU calculating the physics, AI, etc. but really what it does specifically for VR simming on top of the “business as usual” stuff for 2D simming)

Does it do calculations for the 2nd viewpoint?

What is the role of the GPU in this regard (VR simming)? I suppose its main task is to render the image calculated by the CPU, right? And the beefier the GPU the better performance in supersampling, right?

Am I right in saying that if I am happy with my performance right now in terms of FPS, better GPU would not really help getting more FPS (provided my CPU is on top of its %usage) but it would surely help in achieving higher supersampling?

Maybe a dumb question for some but I feel kinda lost :upside_down_face:



i7-4790k no OC, GTX 1080

Gah. This a hard question to answer. It is not easy to separate VR performance into CPU versus GPU so easily.

My initial thoughts (I am not a game or VR developer and this is a (very) simplified view of how I understand things to work - I am somewhat weak in my knowledge of what modern motherboard chipsets do):


  • Primarily is going to be feeding objects and textures to the GPU from storage;
  • It made be deciding what objects are needed but that could also be coming from the GPU;
  • Textures - same thing though these decisions could be coming from the GPU;


  • Primarily the scene layout and special effect rendering - for VR this is going to be offset slightly for each display (eye);
  • I think that the scene is determined by the GPU but years ago, it would have been determined by the CPU;

Again. Very simplified.

It is complicated because you can not simply breakdown/define what task each component is performing. If you have an older CPU (lets say 6 years to stretch the analogy) and a spanking new 2080TI your VR performance is not going to be great because the CPU can’t feed the information to the GPU fast enough to remove itself from the performance calculation. Likewise, if you have a ckick-arse CPU and an older GPU, even though the CPU can feed the GPU fast enough, the GPU can’t generate the images at the resolution required fast enough. So although the CPU “doesn’t have a large role specifically for VR” it is still in the critical path of having to do some work for VR while having to do all the other things that it has to do to make both the computer and game work.

The CPU is a ‘generalist’ device that has to do a lot of things well and fast whereas the GPU has to do only a few few things well and fast.


Tracking comes on top, for both the headset an the controllers.

Basically picture analysis and position sensor calculation in just a few milliseconds.