This might be due to end-to-end encryption:
- Non-beta encryption is implemented with SJCL, which runs in the main JavaScript thread. This may cause the app to run slowly (and sometimes freeze) while decrypting a large amount of information.
- Beta encryption should be faster, but older versions of Joplin won't be able to decrypt notes encrypted with the new encryption methods.
- To prepare for the first sync, the primary master key is decrypted on startup, which can add 1-2 seconds to the startup time.
- This should still be faster than Joplin 2.x with encryption — in Joplin <= 3.0.x, all master keys were decrypted on startup, which could add many seconds to the app's startup time.