[Bakr]

The connection probably isn't only dropping while playing on SA:MP, you just don't notice as you aren't using something that requires a constant connection. If that is the case, which use to be mine, stream a live radio or something alike and see how long it holds. If it disconnects after an amount of time, you know that this is something to do with your internet.

If the above is true, you have the problem I once had. Simply call your ISP and explain to them that your connection is constantly dropping after x amount of minutes. Mine came and juiced up the lines some, and it has been fine ever since.