# Framerate and FreezeRendering

**URL:** <https://forums.unrealengine.com/t/framerate-and-freezerendering/409779>\
**Category:** Debugging, Optimization, & Profiling\
**Tags:** rendering-system, Optimization, fps-drop, unreal-engine, editor, question\
**Created:** [November 16, 2017, 10:23am UTC](https://forums.unrealengine.com/t/framerate-and-freezerendering/409779 "2017-11-16T10:23:08Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![anonymous\_user\_d973a2dd](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_d973a2dd](https://forums.unrealengine.com/u/anonymous_user_d973a2dd)\
**Post date:** [November 16, 2017, 10:23am UTC](https://forums.unrealengine.com/t/framerate-and-freezerendering/409779/1 "2017-11-16T10:23:08Z")

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Hi, i’m working on a vr (htc vive) project and we’re at the optimization state.

We’ve noticed that in our scene, looking from a specific location to a specific direction our framerate drop almost instantly from 90 to 45fps, so we used the freezeRendering command to display just the actors in sight at the specific moment and find out which of these cause the frame dropping.

The curious fact is that after issuing the command the framerate instantly rise again to 90fps, so we can not find the indicted actor in the scene.

Why is this frame rising happening?  
Am i right in saying that it is related to UE not needing to constantly check for which actors are in sight so it gains speed?  
Are there other reasons?

Thanks guys.

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**Author:** ![Etherlord](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Etherlord](https://forums.unrealengine.com/u/Etherlord)\
**Post date:** [November 17, 2017, 2:47pm UTC](https://forums.unrealengine.com/t/framerate-and-freezerendering/409779/2 "2017-11-17T14:47:51Z")

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Hello 🙂  
it`s HMD vsync. I had same prob with oculus. if u can`t hit 90, sometimes you drop to 85 =\> it`s dropped to 45 cause of vsync. Try to turn off this feature for your HMD 🙂

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**Author:** ![jinzay](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@jinzay](https://forums.unrealengine.com/u/jinzay)\
**Post date:** [October 10, 2018, 9:17am UTC](https://forums.unrealengine.com/t/framerate-and-freezerendering/409779/3 "2018-10-10T09:17:17Z")

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Yes this is correct! Its a thing pc vr headsets do to protect you from weird stuttering in vr. Do not turn this feature off! Optimize your scene to run at 90fps. Anything below this should never be accepted.