I personally think that iPad 3 & 4 processor (A5x & A6x respectively) is not that powerful enough to power the high resolution aka Retina Display. THis is the main reason that we might face some lag when we are playing some hardcore high end graphic intensive game.

iPhone in the other hand, due to its lower screen resolution and almost on par processor that is used in the iPad (A6 vs A6x) , but far lower resolution to run the game in, thats why it is pretty easy to get a lag free gaming experience.

So, as long as it is playable, just live with it and no complain Might as well wait for iPad 5 for those who are still considering to buy an iPad 4 now

p/s im hoping to see QUad core CPU in next gen ipad

Haha bro, what i mean and trying to say is that the A5x/A6X processor used in the iPad is not that powerful compared to the A5/A6 used in the iPhone mostly due to the needs to power so big resolution in the ipad compared to in the iphone.

I am not saying that A6 is more powerful than A6x, but is that for its duty, A6 perform more than enough whereas A6x just maybe on the fence and just enough for what it is going to power for

Yup bro, if me, i cant accept as well given the fact that a lower powered A5x in the iPad 3 is capable of running the game smoothly but not the iPad 4
Anyway, please accept my apologize if i did off the track for a bit

But isnt it quite obvious that it might be hardware problem?

Yea, i read this before some where also. But i have yet to see so big difference in the 2. Maybe some splashing of water to the screen when you play riptide GP.