Generally, emulators are available up until the n64/PS1 era. Itll probably be quite a few more years before any later gen systems are emulatable on PC if at all. Its not a matter of power, its a matter of money. Its not that its too complicated to emulate the GC/Xbox/PS2 (the 360 and PS3 can do it), but emus are generally written by bored open sourcers for free, who dont have the time or expertise to undertake such a monumentous task without getting paid for it.