The performance of the server counts of how much ping it has, 1 ping being the best and 100 being terrible I would pick a server with a ping of 20-45 for good performance if that's how you look at it
Having to restart the game every hour, that's not entirely how it works as the game is already using maximum ram when playing rust with 6gb, the recommend minimum is 8gb and then you will be fine
If I was you I would invest in 8gb ram