more than likely the x1300 does NOT require an external power connection
and honestly, that card is gonna do squat for gaming, but it will work pretty good for a Media Center PC
for decent mid-level gaming i would say x1650, 2600, 7600, 8600
mid-high level gaming would be x1900, 2900, hd3850, 7900, 8800gt
if you want to game i would say stay away from the entry level cards like the x1300, 2400, the 6200, 7300, 8300 cards
just my 2 pennies