As long as you are not bottlenecked, two 660ti cards will give you more than 60 fps on many games, especially older games. They will yield more than 60 fps on many newer games, too---on medium to low settings. Also, on a 120+ hz monitor, you get less input lag if you are playing at above 60 fps. Unless you only play the most graphically demanding games at highest settings, I’d say yes, get a 120hz monitor. But just remember, you will be sacrificing perfect/accurate color reproduction for high speed.
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