Need a help in testing possible bug with rendering time

Hello,

found this strange behavior with drastically increasing rendering time when Viewport Shading in Rendered mode.

Test scene

  1. Switch Render Engine to Cycles - GPU Compute
  2. Change View to Solid this time and hit F12.
  3. Remember rendering time or leave, it remember automatically.
  4. Change View to Rendered.
  5. Wait until it stop to render in viewport and then
  6. Hit F12 and watch how rendering becom slow…

My results with NVidia 1650 Super (yes it’s lowend and maybe it’s only my individual problem, so help me to investigate)

Summary

and with Rendered View after it stop to render viewport

Found what is problem. It’s all about VRAM, in Rendered view it not swap before rendering. Told this to developers, hope they make check when F12 is pressed.