[Jstylezzz]

Maybe you have a function that consumes so much resources, that it stops all the other processes. Make sure your server is up to date too, and check where the problem exactly starts. If you know where it starts, you'll be able to solve it.

With the crashdetect plugin, you might be able to find out when the server 'collapses'.

[Tutorial] - Updating your sa-mp server and scripts

Crashdetect