I'm having the same issue after upgrading. The 2 blu-rays I've started are taking 4-5 hours when they were completing in about 30-40 min. I noticed even though I have lightning shrink and CUDA enabled with my NVIDIA GeForce GTX 1060 6GB Driver Version: 26.21.14.3086, the CPU remains above 80-90% when before the update it would remain almost unused as the video card did most of the work. It seems like perhaps even though it says "CUDA GPU acceleration for video coding enabled," it's not really utilizing it. I did also upgrade to the latest nvidia drivers noted above after the first disk (Penguins of Madagascar) took so long, however that did not fix the issue.