Default A501 Performance-Problem

Hello
I have a problem with the performance on my a501 with lost of roms..

currently I use omnirom 4.2.2 and I see that the performance is bad.. I use EVER a clean install...
I noticed that the performance is very very better when I use immersive mode, so I think that the notification bar should make this problems..

immersive mode: performance is very good
normal mode: performance is bad

on some roms with tablet-ui the performance was better as with phablet-ui. I don't know why..
I used some ROMs from here and it was the same problem...

Have someone an idea what I can do or what I can test?