I have weird problem on PC. It looks like Canvas.BuildBatch depends on game resolution. I have animation in canvas so it rebuilds in every frame. In my scene profiler in Editor shows: - for HD(1080p): Canvas.BuildBatch ~ 0ms (or close to it) - for 4K: Canvas.BuildBatch ~ 3-4ms For build it shows even for smaller resolution: even for HD there is Canvas.BuildBatch 3-4ms. But for smaller resolution it disapears. Unfortunatelly there is no source code so I cannot understand why BuildBatch depends on resolution. I tested it on Unity 2018.3.10 and 2018.3.13.