The third generation of the Apple TV is identical on the outside and nearly functionally identical with its predecessor — the only change being the addition of 1080p. That doesn't meant that it's the same on the inside, however, as iFixit's traditional teardown has revealed a few small details changed and an overall refinement of the internals. The first and most obvious change is the switch to a single-core A5 processor to drive that 1080p video (and everything else). Interestingly, the processor no longer has a thermal pad attached to it, suggesting it might run a little cooler than the A4 in the previous generation. iFixit also discovered a second antenna on the device, possibly for 5GHz Wi-Fi.
Otherwise the rest of the internals are the same, including 512MB of RAM and 8GB of storage, and apparently the insides are quite accessible for would-be hackers. With the Apple TV, it's not the insides that count, but the interface — and on that front the lozenge-shaped icons remain as polarizing as ever.