Multiple GPU card problems I have two GPU cards in my machine. I had a GTX 980 Ti and I recently added a GTX 1070. My render times have more than doubled, however when I go back to look at my PNG's, I notice that they don't line up. Every other frame is slightly off in "space" so when the PNG's are run together or if I put them through the video sequence editor, it makes my object shake or slightly move back and forth. Almost like a heat wave effect. Not sure what to do, or if anyone else has seen this.
Problems like this might happen when using different devices to render one frame. That's why render farms have always one type of GPU and/or CPU letting render one frame. If its an animation, lets say frame 1-100, just open Blender 2 times, let one instance of Blender render with one GPU the first half (frame 1-49) and the other instance with the other GPU the other half (frame 50-100).

I never used 2 GPUs though, i dont know if this will work perfectly. But i think so.