its my personal opinion that you should never run your client on the same machine as your server, with the exception of spotchecks on new compiles (such as when developing new cores..) to actually rely on one machine to handle your game,server,mysql not to mention bots and god i hope not additional players is foolish, as unkle says above you are going to have lag under such situations even with a really fast machine.
the point is, there is a limit of how cheap you can be... at some point you are going to have to step up and decide if you are serious or just screwing around, if the you want to be serious, get a couple computers and do it right.
if you decide you are only screwing around, dont waste our time with your inanity