Hey guys, nice thread you got going here - props to Arnar for the testing :D I guess I have run into the same problem. CUDA problems. I am using a desktop machine with 1070 and a laptop with a MX150 I guess. Did some testing and found out the desktop machine just rendering via CPU - GPU was sitting at 0% load all the time (CPU 100%). Combined render took some 2:10min while single render on the desktop took just under 1min. Tweaked the tile sizes to match the "ideal" tile size I tested earlier on every individual system. (256*256 on the 1070 and I guess 128 on the MX150). Still no improvement. After that I was a bit frustrated and took a break, restarded everything and so on ... Eventually I got back into the settings and just unchecked the CUDA device - suprisingly my GPU starts working. Overall I got around 47-49 seconds combined render, both machines set to CUDA and both machines unchecked CUDA checkboxes and both machines got their individual ideal tile size set. By the way my goal was to set everything up to use my desktop as renderer, to accalerate rendertimes while working remotely. Hope this helps, might be a bug with the "inverted checkboxes"? Cheers -b