Below is the "hardware requirements" section from their github page.
**Hardware requirements**
Dendrite in Monolith + SQLite works in a range of environments including iOS and in-browser via WASM.
For small homeserver installations joined on ~10s rooms on matrix.org with ~100s of users in those rooms, including some encrypted rooms:
Memory: uses around 100MB of RAM, with peaks at around 200MB.
Disk space: After a few months of usage, the database grew to around 2GB (in Monolith mode).
CPU: Brief spikes when processing events, typically idles at 1% CPU.
This means Dendrite should comfortably work on things like Raspberry Pis.