Drawbacks/effects of disabling HZBOcclusion?

After analyzing with ProfileGPU, I’ve found that HZB was consuming a big piece of time rendering.
Setting r.HZBOcclusion to 0 greatly increases my FPS.

I’ve tried disabling it in several demos and I could not notice any glitches or problems in the rendered scene. Performance was always increased.

As I’ve read here: What's Submit HZB? It's consuming high GPU resources - Debugging, Optimization, & Profiling - Unreal Engine Forums, HZB Occlusion is a technique supposed to increase performance.

So, is it like this for everyone? Is this HZB Occlusion performance hit a bug on my end (drivers/hardware/settings)? Or could it be a bug in the engine?

Is there any problem with disabling it for everything?
Thank you.


i5 2500k at 4.3ghz

GTX 560 Ti SC

Drivers version: 344.11

Windows 7 SP1

Different scenes may see better performance from disabling HZB occlusion culling. This is due to the conservative but less accurate results it has versus occlusion queries, meaning less objects culled. We have plans to solve this so we can 100% more to HZB occlusion but for now it is left as an option to pick what is best for your content. HZB shines when there are large numbers of objects


Any updates on this? Shouldn’t it be possible for HZB to be almost just as unconservative, other than pop-ins caused by framebehind? Why does it let so many extra primitives through? Is it only doing a limited number of steps, or is it a box vs sphere bounds issue?