Operating system: Windows 10
Graphics card: Radeon RX 580 (8Gb)
Broken: (2.80, release candidate)
Large scenes (>1-2 km) are incredibly slow in blender 2.8 compared to 2.79. I imagine the problem is because of two things: the lack of a LOD system, and texture rendering. It basically kills hope of making cinematic city scenes, landscape scenes, forest, etc. I've seen this problem on multiple computers running 2.8, so it doesn't seem to be a machine-dependent issue with processing.
Create a scene larger than 1km or 2km and set the clipping distance to about 2km. Add a few hundred thousand polygons to the scene. Add materials and textures. Watch Blender cry.
I used the Scenecity addon to great frustration, and you could likely reproduce it with that.