# VTK 8.2, performance degradation on upgrade Qt 5.12 -\> 5.15

**URL:** https://discourse.vtk.org/t/vtk-8-2-performance-degradation-on-upgrade-qt-5-12-5-15/8536
**Category:** Support
**Created:** [May 20, 2022, 1:41pm UTC](https://discourse.vtk.org/t/vtk-8-2-performance-degradation-on-upgrade-qt-5-12-5-15/8536 "2022-05-20T13:41:55Z")
**Posts on this page:** 1
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### Author: ![lassoan](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lassoan/32/50_2.png) [@lassoan](https://discourse.vtk.org/u/lassoan)
#### Post date: [May 21, 2022, 1:15pm UTC](https://discourse.vtk.org/t/vtk-8-2-performance-degradation-on-upgrade-qt-5-12-5-15/8536/3 "2022-05-21T13:15:35Z")

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We have not noticed such performance degradation in 3D Slicer when switching from 5.12 to 5.15 on Windows. Linux and macOS users did not report slowdown either. So, it is unlikely to be a widespread general issue with Qt-5.15.

What differences do you see in performance profiling results? Where the most time is spent?

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