Hi guys!
I have two kodi boxes at home. One is very old Amd 3530 setup and I just bought i5, 8gb, ssd. I also use kodi on my widows machines. On every one I use Arctic Horizion 2 skin (but i really doesn't really matter that much because on other skins you can see also this problem - the more animation skin got its worse).
The problem is somehow hard to describe. It's about how GUI animation are handled. Arctic Horizion 2 have a lot of animations. When my GUI is set to 1080p animations are not smooth like they should be on machine like i5 (cpu usage is like 2-3% when in gui and even on 4k videos it never extend 10%). Animations are like I was on pi or something 
I thought that my AMD 3530 was old so that's why I bought new box and it's much much faster overall but animations are exactly same. I tried instaling windows on this i5 and even on 4k GUI settings everything is smooth as butter. So I ruled out hardware issues. I tried every single resolution on libreelec i5 setup and what I found was that on 720p GUI animations are what they should be, but then I'm on i5 and 4k tv and using 720p GUI doesn't sound and look right:)? Then I did a little test and on AMD 3530 on libreleec I changed GuI resolution to 720p and BAM !! Perfectly smooth!!! All this time I thought my 3530 was slow so I didn't really cared
Do you have any idea why on windows animation are perfect and on libreelec don't? Is it windows - directx and libreelec - opengl related?