Graphics card light upgrade

[ThinkPad560X]

I have a Nvidia GeForce 580 1.50GB GDDR5, I picked up a Nvidia GeForce GT 640 2GB DDR3 Super Clocked for dirt cheap and like new hardly used. I took apart the 580 and cleaned /added new thermal paste on it to keep it cool. But the card uses 600W and the 640 uses 300W. I was wondering if this card would be fine for playing all the way up to fallout 4 and maybe outer worlds if I would sell the 580. I don't play games much but if do these are the latest titles I have. Fallout New Vegas should be fine on any of these cards as I already been playing it on the 580 at max.

The plus with the 640 is it is 2GB and a smaller footprint in the tower compared to the 10-1/2 long 580 and the 300W lower usage.

I would get a new card, at least from 2019+, but the prices are very high.