The Botanist Blog: Tuning Phaser Performance
"The biggest performance killer is the smooth-scrolling camera follow mode. Scrolling has to be perfectly smooth, running as close as possible to 60 FPS with little variation, otherwise it’s really noticable. Scrolling, in general, is a hard problem, and is in fact one of the biggest CPU hogs in everyday desktop computer usage as well."
"I wrote recently about a mobile-efficient camera scroll, which avoids smooth scrolling altogether and really improves the mobile experience, but I want to get smooth scrolling working really well on desktop platforms. The bulk of my testing so far is in Chrome and Firefox, so most of this post is about Firefox."