Trying to compile a PBR shader in Blender 2.83.4. The CUDA optimization is set for both the processor and graphic card (AMD Ryzen5 3600 and GeforceGTX 1660). Plugging several masking nodes into the Color channel does not load the GPU too much(although I can feel some minor slowdown). But when I plug in the BUMP node - everything starts to lag and the GPU load peaks to 100%. Surprisingly enough it is the same for 2.91 ALpha. But when I open the same scene in 2.8 - everything is lightning-fast. Friends, maybe you have had the same issue? Is it hardware,driver-related or just a bug, they made after version 2.8? Is there any workaround, because why roll back to the older version if the new ones should be more stable?
Thank you. Skull_PBR

  • $\begingroup$ Try going into eevee renderer, performance and untick the high quality normals. $\endgroup$ – Mobin Aug 8 '20 at 7:13
  • $\begingroup$ 2.9 Alpha (not even beta) is not going to be more stable, as is still work in progress. Some things break on "experimental versions", or might be buggier. Release versions are in general more stable. $\endgroup$ – no-can-do Aug 8 '20 at 7:24
  • $\begingroup$ @Mobin yeah, I did not even turn it on. Interestingly enough - this slowdown starts with version 2.81. In version 2.8 everything compiles very fast - I don't even see the process of shaders compilation - they fire up right away. $\endgroup$ – Sergei Kritzien Aug 8 '20 at 7:31
  • $\begingroup$ yeah I have the same slow downs in one of my blend files too. it uses bump. I think you should report this. $\endgroup$ – Mobin Aug 8 '20 at 7:39
  • $\begingroup$ The answer from bug report team: "This was an intentional change in 2.81 in order to improve the quality of the bump node. While we do continue to work on improving performance in general, potential performance improvements are not handled as bug reports. To improve performance, consider using less complex geometry, simpler shaders and smaller textures." - In other words Bump node in Eevee is unusable and it's not gonna change in nearest future. Stick with Substance for texturing. $\endgroup$ – Sergei Kritzien Aug 8 '20 at 9:55

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