I have the following scene where a light ray is being scattered behind a glass. The whole scene renders pretty fast, tiles on non-glass materials only takes a few minutes to finish. However when it comes to rendering the glass it becomes super slow, tiles been stuck there for the majority of 5 hours now (screenshot below).
Using 2000 samples, indirect clamp to 4 and max bounces at 6. Refractions without the volume scattering also renders pretty quick.
CPU: 4770k at 4.0GHz
GPU: 780Ti 3GB
Is this a known bug? Are there any tips or workarounds to speed up the render times when it comes to refractions, without sacrificing much quality? Thanks in advance.