hi,i am planning to upgrade my graphic card to gtx 650(as that's the only one available quick)...i want to play games such as assassins creed 3, hitman absolution, alan wake at max settings at resolution 1600 x 900 .Will i be able to do so .my computer specs are:-
ram:-kingston ddr3 6 gb
power supply:-coolermaster 600w thunder
The CPU can make a huge difference in FPS... but it depends on the game. Some games are very CPU intensive, while others are more GPU intensive. In other words you could have the top of the line GPU like a GTX 690 or AMD 7990, but have a crap CPU and only get 10 FPS...
Overclocking will help, but a 10% increase in performance when you are getting 20 FPS... is only going to raise it to 22 FPS. The GTX 650 will work but you will need to move some of your settings down to get playable FPS.
I can't find a review with the games you have listed but all other new games at your resolution it shows the card getting right around 20 FPS... with high settings. You could always play at low-medium settings and get maybe 30-40 FPS..
30-60fps is generally what you should be shooting for. If the only reason you are buying that card is because you want it quickly then I would tell you to have some patience and order at least a 660 or 560ti. If it is more of an issue of price than getting it right now you may want to consider something from last gen or an ATI card.