Here is a more complex scene.
This is pretty much a worst-case test for raytracing, lots of Glass, caustics, reflections from caustics, volumetric materials and many small light sources.
Again, GPU only (CPU has no performance improvements over the normal Blender builds).
Windows 10
Nvidia GTX 980 with 4GB
900 Samples
Normal Cycles: Time: 40:04.81 Peak Memory: 643.69M
E-Cycles Time: 25:13.23 Peak Memory: 655.70M
The Speedup is amazing
E-Cycles looks indeed a lot cleaner with the same sample values especially on the glass.
Cycles is always biased. As soon as any render engine is tracing shadow rays, it is actively looking for light sources and therefore it’s biased. This doesn’t mean that this is bad in any way, it’s actually smart.