# Using vtkRenderer and vtkOpenGLRenderer

**URL:** https://discourse.vtk.org/t/using-vtkrenderer-and-vtkopenglrenderer/12805
**Category:** Support
**Created:** [November 29, 2023, 8:35am UTC](https://discourse.vtk.org/t/using-vtkrenderer-and-vtkopenglrenderer/12805 "2023-11-29T08:35:15Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Hedwig\_Huang](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hedwig_huang/32/7745_2.png) [@Hedwig\_Huang](https://discourse.vtk.org/u/Hedwig_Huang)
#### Post date: [November 29, 2023, 8:35am UTC](https://discourse.vtk.org/t/using-vtkrenderer-and-vtkopenglrenderer/12805/1 "2023-11-29T08:35:15Z")

</div>

Hi there, I upgrade VTK8.2 from VTK8.0 and my project successfully compiled and run. But I found something interesting, like when just replacing libraries, the CPU memory usage is increasing from 7-10% to 20-30%, and the frequency went very slow sometimes.  
Then I tried to put these things to GPU to speed up, with changing the Renderer from `vtkRenderer` to `vtkOpenGLRenderer`, the same as the `vtkRenderWindow`.  
Then the CPU usage decrease back to 7-10%. But the GPU usage didn’t change much, like about taking 20-40% around.  
How could that be?