Last year ago, I did use Digital Ocean services and it was messed up due to unknown reason, like, server shut down with no errors or java errors. Until figure out that Ram is not enough even though already add Swap Ram.

So I`m back again, with plan to get 4GB VPS Server. This time, I like to ask friends about this.
I wanted to ask, since I plan to make this server a 1-100 players,
4GB Server is enough to make a server or no, or should I get 6GB instead?

If its not enough, any suggestion for the improvements?
Thanks :)

OS Preference : CentOS 6 64-bit
Ram Suggestion : 4-6GB rams
Player Based : 1 to 100 players.
Connection : Singapore