updated 04:50 pm EDT, Thu November 1, 2012
Borrows tech from revised iPad 2
A Chipworks teardown of the iPad mini has confirmed that the A5 processor in the tablet is a 32nm design manufactured by Samsung. The A5 premiered in the iPad 2, but was originally produced using a 45nm manufacturing process. The switch to 32nm happened around the same time the third-generation iPad was introduced, retrofitting the iPad 2 with improved power efficiency and battery life.
The third-gen iPad uses a 45nm A5X chip, but the A6 in the iPhone 5 is another 32nm design. It's uncertain if the A6X in the fourth-gen iPad has reverted back to 45nm, since no teardown of the tablet has been done yet.