I installed the last version of MIUI V5, but it was a littel bit slow. In antutu it gives me around 13500 points. So i flashed 1.4 stable kernel by enyxos but the phone stuck after CELLEON logo. What I am using right now is V5 and QLyine kernel with cpu speed of 1400(it cant be more), Apex launcher and also disable some of nativ apps in MIUI. For now everityng is OK and there is no a lot of lag. In antutu it gives me aroudn 17 000.