It could either be a RAM issue or your processor. However, I think it's a RAM issue because if it were a something to do with the processor -- you should only experience a severe drop in your FPS.
Apple products (though I hate Apple)is great when it comes to running apps. However, I would stick with Androids. Before you buy one, make sure to check out the specs. Compare and buy the best accordingly (without breaking the bank). Or if you're feeling up to it, buy a new ramchip set and install it yourself. That's the method I'd do.