我遇到了同样的问题，遇到了WWDC 2013会议509注释， http://asciiwwdc.com/2013/sessions/509 ：

I had the same question and came across this WWDC 2013 session 509 comment, http://asciiwwdc.com/2013/sessions/509 :

请注意，Core Animation和Core Image都充分利用了GPU。

"And also be aware that both Core Animation and Core Image both make extensive use of the GPU.

因此，如果您希望Core Animations变得流畅，则可以错开Core Image操作或使用CPU CIContext，以便它们不会同时对GPU施加压力。

So if you want your Core Animations to be smooth, you want to either stagger your Core Image operations or use a CPU CIContext so that they don't put pressure on the GPU at the same time."