Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: 2x GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.86
Broken: version: 2.81 (sub 14), branch: master, commit date: 2019-10-06 14:05, hash: rB54a9649e2636
Short description of error
I've noticed that certain (very complex) shader node setups yield much longer render times on the current experimental build compared with the 2.80 stable release.
To demonstrate this, I've deliberately created a complex test shader with various layers of nested node groups (which perform a bunch of mathematical operations with Math nodes). The final output is just a black cube.
Rendering the exact same file on my machine (specs listed above) with both stable release and experimental build yields following render times:
Average render time with 2.80.75 stable release: 0.48 seconds
Average render time with latest experimental build: 4.30 seconds
Exact steps for others to reproduce the error
- Download & open attached .blend file
- Render on both stable release & latest experimental build
- Compare results