The A5 in the iPad is different from the A5 that will be in the iPhone 5.
The A5 in the iPad 2 uses a PowerVR SGX 543MP2, while by all indications, due to thermal and battery considerations, the iPhone 5 will use a PowerVR SGX 543 -- 4 SIMD units vs 8 in the iPad 2.
We don't know what the iPhone 5 will have. No one does.
