I tested the kernel comes with this rom too but same result. Actually im playing Modern Combat 5 with 60 fps, 100% render scale & optimal gfx. With 80% rendering & performance gfx it got no lag at all but the graphic becomes terrible..
No I disagree with the rumour. I used to play games in stock lollipop rom without having lag issue with games under 100mb. Not sure with 'heavy' games..