Btw - does it have to be a laptop? If only for SH3?
For the money you should get better eqipment - cpu and graphics - combined with a smaller HD in a dektop computer.
Or you may save money and lag around like Acer 511...
Oh - reading your first post again - you may use Bootcamp with Win 7 or 8.x and save even more money.
Or even cheaper - have you ever tried
Wine?