The Mac really needs GPU support

2 Hour + video file in 4K (UHD) weighing in around 40 gigabytes. It’s taking Handbrake 12+ hours to transcode from MKV to MPEG4. This is a 4Ghz Core i7 iMac Retina and I have a Radeon M395X with 4 gigabytes of VRAM just sitting there idle. It’s a travesty that I can’t take advantage of that power. Encodes would finish twice as fast.