On iOS 13 / 13.1, requestAnimationFrame runs at 90 Hz when low power mode is enabled. Demo URL: https://www.scirra.com/labs/bugs/safari13raf/index.html Steps to reproduce: 1. Ensure low power mode is disabled 2. Visit demo URL in Safari and observe FPS reading is 60 (tested on an iPhone 7 Plus, which has a display rate of 60 Hz) 3. Go to settings and enable low power mode 4. Switch back to Safari Expected result: FPS reading either the same or dropping to 30 (as I believe previous releases did) Observed result: FPS reading is now about 90 FPS, which is higher than the display rate of the device. Originally discovered in this tweet: https://twitter.com/chribbe1/status/1176767527797579776 The issue appears to affect several web frameworks, indicating a general problem with requestAnimationFrame. I suspect a new 30 Hz timer is being set, but the old 60 Hz timer is not cancelled, resulting in adding together to make a 90 Hz callback frequency.