[Michael B]

You'll better host more 100 slots server. However, it is not good to predict what's the limit, because each SA-MP server consumes performance depending on what plugins runs, what's the lenght of the gamemode, how many objetcs do stream and also, what's the number of connected players and NPCs.
Judging by your device, I think you could support 1000 players online at once with no lag (depends on the server though, as I said above).