iOS 9.2.1 slow my iphone 6

I just can`t stand how bad my iphone is working with IOS9.2.1

My wife Iphone5c is more fluid with 8.4 than my iphone 6 with 9.2.1.

when i leave the phone a few hs without using it and i unlock it, it stutter the animtions are lower frames than with IOS 8.4.1

I already tried

1.-Reset all settings

2.-Hard reset

3,restore from early Backup

4.-Restore and clean install (install apps manually).

The last step seems to make the phone work better but it last a few hs untill i started installing my apps,then it became the same stuttering/lagg mess.

Any other thing i could try? I don`t understand how people say it runs fine, or they don`t remember how fluid 8.4.1 was or i`m being too picky.

Personally i read that Apple is using METAL for all UI instead of OpenGL, this seems to be the reason since the lag is everywhere not only on specific apps.

Facebook, tweeter, and many more srcolling had little pauses when a video was posted. before it was silk smooth.