Background rendering longer 10 times than UI rendering

Hello
Please help me to solve this problem.
I run several scenes in background render via “blender -b my.blend -a”
And get veeeeryyy long rendering time.
Why?
This is my scene (559MB) https://yadi.sk/d/9vPLDCvjhh3Yx
Please test it to compare background and ui render times
Thank you