Behind The Pixelary — Improving performance of Blender's Cycles...
Blender 2.80 hybrid (CPU+GPU) rendering - speed and quality | RenderStreet Blog
4 Easy Ways to Speed Up Cycles — Blender Guru
Hardware Recommendations for Blender | Puget Systems
What CPU and GPU are suitable for 3D modeling and rendering? Which ones are the best out there and which ones are good enough for beginners who are getting started in 3D
Behind The Pixelary — CPU vs GPU rendering in Blender Cycles
Cycles X Project Update — Developer Blog
rendering - Blender 2.8 uses CPU rather than GPU, contradicting with settings - Blender Stack Exchange