There are two types of lags:

1. too many relays sending the exact same info to you. Bugger the amount of messages / sec the worse it gets.

2. Memory limits. If you are using Amethyst for too long without a restart, it starts to hit the ceiling

3. Disk storage. When it gets close to 1gb, android goes a little crazy with lags

1. Reduce relays

2. Close the app when it happens and let it load again

3. Clear disk cache on settings.