Hello, I just bought a xiaomi mi4c. The ram is 3GB, but there are always 1.5-2GB occupied, so that I can use less than half of the memory. I can't find a page that tell me how is used this ram, do you know where should I search for it?
Have bought a Mi4C recently and by default I have roughly the same memory usage.
Then again I find the phone running butter-like smooth.
Been searching around the internet on this matter which initially concerned me too, but about everywhere I read that android, being Linux-based, consumes as much memory as it can.
So I think this should not worry you, but from "Settings" --> "installed Apps" you can see exactly which apps consume memory and you can always close most apps from there or freeze them with for instance Titanium Backup (Pro).
Although relatively old but still quite relevant, for background info on this matter, google the article "RAM: What it is, how it's used, and why you shouldn't care" and take note of the statement therein 'Unused ram is wasted ram'.
(can't post the link because I haven't posted more than 10 items yet...)
Hopes this helps...