I've a reasonably complex main menu and customisation UI with several panels layered and scroll views. I've packed all sprites with the sprite packing tag 'UI'. When run on a 2013 Nexus 7, the refresh is really sluggish. There are about 90 batches. Before using Unity's new GUI, I've used NGUI and it gives much faster results, drawing everything in a handful of batches. Is there an optimisation step I'm missing?