Be aware that the i5 in the video linked by alexoiu was overclocked from its stock 2.66ghz to 4.2ghz, an almost 60% OC.
At this point the 1st gen i5's are around 8 years old, and both clockspeed and performance per clock has improved significantly since then. That's not to say many games won't run well enough, but it depends entirely on which game.
How much are you paying for the i5 and 760?