Blender 2.78b Release Notes

Blender 2.78b is a performance update release which mainly includes speedups for Cycles rendering.

Cycles

Multithreaded shader compilation.
Various optimizations for emission meshes.
Corrected light sampling for Branched Path Tracing, reduces noise leading to faster convergency.
Improvements in constant folding algorithm, removing shading nodes which are not used for final evaluaiton.
Improvements to some procedural textures (brick)
Early light ray termination based on contribution of light to the result.
Fix for background MIS with textures having small bright spots, which was causing fireflies.
Different seed for subframes and different stereo views, allowing "slow-motion" effect and improves VR experience.
Distance culling for objects to remove objects which are too far away from the camera.
Fix for undesirable threads affinity change on Windows.
Avoid various numerical issues in the kernel, solving fireflies.
Fixes for deformation motion blur combined with autosplit.
Better remainedtime estimation.
Various optimizations for deformation motion blur.
Added time steps BVH option to speed up rendering of scenes with motion blur.
Hair particle settings were moved to Geometry panel of Render context.
Beckmann/GGX distribution with 0 roughness is now considered a singular ray

Use XDG folder for cache on Linux and OSX, which avoids having per-Blender version folder with all the OpenCL/CUDA kernels built.
Ability to enable/disable individual GPUs as opposite to old behavior with pre-defined combinations only. Not only this helps to some artists, but also makes it possible to have flexible benchmark scripting.

Use more global SSE optimizations for SSE4.1+ kernels.
Multiple improvements for the latest AVX2 CPUS:
- Optimized various math utilities (cross-products, dot-products, min-axis-selection and others).
- Faster version of triangle intersection function.
- Optimization of various steps in BVH traversal algorithm (including both construction and traversal).

Added 3D textures support for OpenCL
Make it conditional to compile-in transparent shadows support. Depending on a scene and hardware gives really major render time improvements.

Solve various race conditions (conflicts between threads which are working on the same data).
Optimization of dependency graph construction time.
Fix missing or wrong relation links, which were causing hard-to-reproduce bone flickering.
Fix various crashes related on linked data blocks.
Fixes for missing animation updates.