Slow updates in case of 400k Result

In my Android app I have a RealmResult on the main thread which takes about 5 seconds to query (in the background, due to a sort on it) and I have a changeListener on it.

If I change in the background one of the items it takes again about 5+ seconds to get notified. This leads to a poor UX. I’m sure there is a solution, but could anybody give me a hint where to start the optimization?

I’m using v6.0.2

Regards,
Szabolcs