Unhappy [Q] LAG makes me go CrazzY!!!! HELP

I've changed a lot of Roms and did a lot of kernel combos...... from 2.3.6 to the latest 4.4.2 ..... But Lag my mortal nemesis had always been a close companion to me! I want a Setting of my device Nexus S i9020a SHW-M200, to produce its max. power...... Im a heavy gamer.... so i dont want games like Modern Warfare 4, GTA Vice City, Real Racing 3 and The Dark Knight etc... To Lag on my device... I've seen certain videos on Youtube whose Nexus S was running these games with ease and no lag..... I need to have a solution Plz help........

Current Rom: Stock 2.3.6 (Because im fed up from changing roms every 3 days)
Kernel: FrancisoFranco