# RT - how to get 100% GPU/CPU usage?

**URL:** <https://forums.chaos.com/t/rt-how-to-get-100-gpu-cpu-usage/53275>\
**Category:** General\
**Created:** [April 1, 2015, 11:48am UTC](https://forums.chaos.com/t/rt-how-to-get-100-gpu-cpu-usage/53275 "2015-04-01T11:48:03Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Micha](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/micha/32/59168_2.png) [@Micha](https://forums.chaos.com/u/Micha)\
**Post date:** [April 1, 2015, 11:48am UTC](https://forums.chaos.com/t/rt-how-to-get-100-gpu-cpu-usage/53275/1 "2015-04-01T11:48:03Z")

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Hi,

I setup a simple scene with a plane, a box and a dome light with HDRI. Why I don’t get 100% GPU or CPU usage? The usage is around 40%..70% only.

Ciao,  
Micha

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<div class="post-metadata">

**Author:** ![svetlozar.draganov](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/svetlozar.draganov/32/53004_2.png) [@svetlozar.draganov](https://forums.chaos.com/u/svetlozar.draganov)\
**Post date:** [April 4, 2015, 7:30pm UTC](https://forums.chaos.com/t/rt-how-to-get-100-gpu-cpu-usage/53275/2 "2015-04-04T19:30:06Z")

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Have you played with the Performance Settings(Ray Bundle Size / Rays Per Pixel)?

> **[Chaos Docs](https://documentation.chaos.com/)**

Higher values should increase the CPU/GPU usage lower should decrease it.  
What RT engine you are using?