Updated: read our iPad review.
The two devices are pretty similar in many ways, so we thought we'd do a straight-down-the-line comparison of the raw specs to see what's been enhanced for the iPad.
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There's not as much difference here as you might think, despite the iPad having Apple-designed silicon inside. The iPhone 3GS has a Samsung S5PC100 chipset alongside a Samsung-made ARM Cortex-A8-based chip. That pootles along at 600MHz – unfortunately underclocked.
The iPad introduces the first spoils of Apple's 2008 acquisition of semiconductor company P.A. Semi. The Apple A4 is also ARM-based (rumoured but not confirmed to be another Cortex-A8-based chip) but runs at 1GHz. It's a fully-integrated system-on-a-chip (SoC), again rumoured to be made by Samsung for Apple.
By the way, the older iPhone 3G ran a slower ARM 11-based chip clocked at 412MHz.
Like the iPhone, the iPad will have a PowerVR SGX graphics chip, but the spec is not known as yet. This is pretty crucial, as many applications so far developed for the iPad will have had to run on emulation rather than the hardware itself. That's an interesting challenge for developers, especially those producing games for the new device.
The iPhone 3GS comes loaded with 16GB or 32GB of Toshiba-manufactured flash storage, while the iPad adds a 64GB option. We'd expect a high end variant of the next iPhone to pack 64GB. The iPhone has 256MB of RAM, but as yet we don't know how much the iPad will have.
The iPhone's 3.5-inch widescreen Multi-Touch 480 x 320 display is obviously dwarfed by the 1024 x 768 pixel resolution of the 9.7-inch LED-backlit display of the iPad. Both have the same fingerprint-resistant oleophobic coating. We're looking forward to seeing the iPad's screen for real.
As we know, there will be two versions of the iPad, the more expensive of which will pack 3G capabilities in addition to Wi-Fi. Like the 3GS (and indeed the 3G), there will be Assisted GPS. Both iPad variants will also have the digital compass from the 3GS alongside the accelerometer found in all iPhones.
Buttons and other hardware
Like the iPhone, the iPad also has an ambient light sensor, but you don't get the proximity sensor the iPhone uses when it's close to your face to turn off the screen – not that you need it. As well as the standard dock connector, volume control, Home button and sleep/wake button straight off the iPhone, the iPad replaces the mute control from the iPhone with a screen orientation lock. We wish we had that one on the iPhone, too.
Size and weight
Not surprisingly, this one's where the difference between the two pieces of hardware is most in evidence. Interestingly, the iPad with 3G carries a weight premium of 50g over the standard Wi-Fi model and also has a black plastic area along the top of the back side for the antenna. The iPad is also only a tiny, tiny bit thicker (1.1mm) than the iPhone 3GS. Full specs below.
Height: 115.5 mm (4.5 inches)
Width: 62.1 mm (2.4 inches)
Depth: 12.3 mm (0.48 inch)
Weight: 135 grams (4.8 ounces)
Height: 242.8 mm (9.56 inches)
Width: 189.7 mm (7.47 inches)
Depth: 13.4 mm (0.5 inch)
Weight: 680g (1.5 pounds) for Wi-Fi model, 730g (1.6 pounds) for the Wi-Fi and 3G model
The key comparison spec here is standby time. The iPhone can stay active for up to 300 hours according to Apple, though the company obviously uses different iPhones than the rest of us. Sadly there's no such detail for the iPad yet – is there something Apple doesn't want to tell us? Again, official specs below.
Talk time : 12 hours on 2G, 5 hours on 3G
Internet: 5 hours on 3G, 9 hours on Wi-Fi
Video playback: up to 10 hours
Audio playback: up to 30 hours
Up to 10 hours of surfing the web on Wi-Fi, watching video or listening to music