Comment by citrin_ru

Thanks for this insight. It's very counter intuitive. Normally transparency is additional work for a GPU.

I had "Reduce Transparency" check-box in settings turned on because I distaste semit-transparent interfaces. Was not noticing performance problems except one application - Ogranics Maps which were unusably slow after switching to another app and returning to maps so I had to restart it freqently (swipe up). I was thinking that the problem is with Ogranics Maps code.

After seeing this comment re-enabled transparency (iOS default) and Ogranics Maps working fast even if I switch between Organic Maps and other apps!