I just did 50 samples and it to 1 hour and 33 minutes to render. My GPU couldn’t handle the render but my CPU could. I thought I had a pretty good GPU (Geforce GTX 1060 with 6 GB of RAM) but the memory used in the Blender file was 772 MB. My CPU (i7-770K @4.20GHz and 32.0 GB of RAM) had no problem. I also only renedered at 50% Resolution. I quickly checked 100% resolution at 200 samples and that would have taken close to 18 hours to do. Not happy about that at all! 
