notedeck itself doesn't really do any heavy processing. most of that is done by nostrdb in C in a threadpool (note parsing, sig validation, etc). all notedeck does it talk to the local relay and fetch things from the memory-mapped database with 0 serialization in and out since its all flatbuffers. the result is that the UI is 144fps+ consistent when scrolling. I built notedeck from the ground up with performance in mind. it even runs at max framerate on the slowest android devices I could find. 

 Is it possible to have nostrdb live on an Umbrel for example, and make all Damus instances (phone, tablet, pc) talk to it on a local network. 

Like a shared DB always connected even if apps are closed. 

 You can just use strfry or nostr-rs-relay, those are great for personal relays. nostrdb is more meant as an in-process relay for high performance use cases 

 I’ll look into that. Thanks.