Xiaomi Mi 5s Not Always Reactive And Fast

Mar 18, 2016
I have a Mi 5s device with xiaomi.eu dev rom. I used to have Android 6.x at the time I purchased it. the devic was always functioning very fast and reactive in anything I used it for. I then upgraded it to Android 7.x (clean install from scratch) and up to now I noticed that not always it is reactive and fast as I should expect it to be according to hardware specs. I regularly perform weekly updates, clear cache and dalvik, install root....

Here one example to better explain. I wake the device up and try to load camera. Sometimes, camera app sits there for three seconds more/less till I can star using it. Another one: I open the Gallery app for watching pictures and from time to time it takes few seconds till I am able to see them.

Has anyone experienced this or a similar issue? Is there a way to try finding out what is happening on my device? Perhaps a specific tool that monitors the entire system and let me consult later on logs or what has the device done? Is this just due to the rom?
I wonder if I install a different rom if this device will occasionally behave the same

Thank you