See comment for exact details and project:

'lowp skinning' test has regressed by ~ 10% somewhere in the 5.6 release cycle:

avg. frametime:

5.5.2p2 - 38.468ms
--
5.6.0b1 - 59.619ms
5.6.0b4 - 63.634ms
5.6.0b5 - 51.703ms
5.6.0b6 - 42.402ms

5.6.0b10 - 42.627ms
5.6.0f1 - 38.603
--
2017.1.a1 - 46.05
2017.1.b4 - 44.191

This seems to have been fixed on 5.6 before public release, but the regression seems to still be present on 2017.1 ( see the link for exact changesets)

Tested and reproducible with Metal on iPhone 7 and iPad Air 1