How is it that the LE interface is so exceptionally fluid and Android is like a slide show?
You will find S905 AMLogic Android boxes run the Mali-450 GPU at 500MHz or even lower, using a GPU load scaling Mode of 1 - which means a 1080p interface or worse 4K is drawn onscreen pretty slowly. RAM quality and speed also makes a difference.
Even worse is AMLogic Android devices seem to artificially constrain the Max. GPU limit to 666MHz with the device trees they use, when the max AMLogic marketed limit is actually 792MHz. We modify the device trees we use in LE to use 792MHz
If you have not already had a look on LE Kodi > Settings > System > AMLogic > you can crank the GPU up to 792MHz
Next we use a CPU Performance Governor by default vs the stupid Hotplug Governor Android media players use, which in reality is designed for battery life on mobile devices.
Hotplug makes no sense on a mains powered media player. Maybe it's also for SoC heat control which is poorly implemented on cheap ARM devices, especially cheap AML S912's that have lots of Cores.
The Android OS is a resource hog that runs comparatively slow on low powered ARM devices. It's gotten a bit better with Android Oreo now Google have gotten off their asses and started optimising a few things, to appeal to a wider Android TV media player / TV audience.
The fairly modern (buggy) v4.9.x Linux Kernel in AMLogic S9xx Android Oreo likely helps.
Having said all that, it's a real pity we do not have Native Linux GPU drivers for the Mali-T820 GPU in the S912's.
Tickle the GPU MHz in Android on those and they are pretty damn snappy because of the included ARM tech in the more modern GPU, that also has better memory bandwidth.
This Kodi ARM Tech Article makes for interesting reading:
Kodi's Dirty Regions - ARM GPU Tech - improving Kodi rendering performance