What will an i3 paired with a geforce gt 640 run. i wont be playing many intensive games (tf2, minecraft etc. maybe mw3, skyrim and crisis) will these run or should i get an i5 with a gtx 660 although it would be stretching my budget. also would an i5 perform better with the 640?
TF2 and Minecraft should run fine with a GT 640 and an i3, but im not too sure about skyrim and crysis. You wouldn't see much of a difference in gaming whether you have an i5 or and i3 when paired up with a GT 640. But if you get the i5 with the GTX 660, you'll notice somewhat of a performance boost.
Short answer : It would be better for your budget and for general gaming performance to get an i3 with a GTX660. An I5 would improve gaming, but to keep the gaming performance/price to the best possible the i3 is a better option.
Longer answer : Most games can not even use all 4 cores an I5 has to offer and for light gaming an I5 is overkill. Graphics cards is what determines the biggest performance in games.
Full answer : if you would like me to explain it in full detail. Ask.
BUT before you decide and expect a better answer please answer the following.
What resolution will you be playing these games at?
WOuld you like some future proofing from this purchase?
Do you like the settings of games as high as possible?(keeping cost and budget in mind)
Another thing is the AMD competing cards at the GT640 range are much better in my opinion. At the GTX650 and up there are more things to consider.