One of the most important things to remember is you share the connection with other people in the same house is that whatever they're doing can affect your speed. ie. Skype.. WOW.. YouTube.. Torrents..
So remember to unplug them first if you want a lag free experience.

Also, just because the other guy is in Malaysia doesn't mean that your connection will be lag free. Depending on what provider they use, the connection might still be shit ie. Some of those condo broadband providers.