Nah, it's both 10-bit and dithered, promise. See the Apple reference documentation I just posted above. You can tell by comparing a test image across the 4K an

Nah, it's both 10-bit and dithered, promise. See the Apple reference documentation I just posted above. You can tell by comparing a test image across the 4K and 5K iMacs. I first discovered this by doing that comparison at an Apple Store. There's obvious banding on the 4K model that isn't there on the 5K model.