The iPhone 4S uses pentalobe screws.

iFixit managed to get their hands on an iPhone 4S so that they could do a complete teardown. The exploration reveals a couple of interesting finds. One of which is that the iPhone 4S definitely comes with 512MB of RAM. This is the same amount of RAM that comes loaded in the iPhone 4. This amount of RAM seems so do more than a fair share of good for the phone as is. It's not surprising that they would opt to stay with 512MB. You can multitask and play demanding games with ease.

Of course, the A5 processor is a huge part of the teardown. What would a teardown be without the most important part of the iPhone? The iPhone 4S's A5 chip is an underclocked dual core 1Ghz processor, throttled down to 800Mhz. The chip offers 2x faster speeds of the iPhone 4's 800Mhz single core A4 chip, and 7-8x faster graphics rendering. Game developers like Chair, author of Infinity Blade, are taking advantage of these awesome increases.

The logic board also holds another surprise. It comes with a Qualcomm RTR8605 Multi-band/mode RF Transceiver. The Qualcomm chip has been upgraded from MDM6600 to MDM6010. The logic board seems to look very similar to the CDMA iPhone 4's logic board.

The vibrator in the iPhone 4S is the same vibrator that we find in the Verizon iPhone 4. It's a linear osculating vibrator instead of the rotational electric motor with the counterweight found in the AT&T iPhone 4. According to iFixit, the linear osculating vibrator is quieter and less annoying. But personally I feel the counter-weighted one is easier to feel when you get a text message in your pocket.

The 8 Megapixel camera is of course there and a complete upgrade from the iPhone 4's. Although, the front facing camera is the same VGA-quality FaceTime camera found in the iPhone 4.

The battery in the iPhone 4S is also a bit better than the iPhone 4's. It has another .05 W/hrs than the iPhone 4's battery which allows you get 8 hours of 3G talk time instead of the iPhone 4's 7 hours of 3G talk time.

Sources: iFixit