We stripped down the iPhone 4 to its basic components. Apple definitely spent time giving the phone a thorough makeover, meticulously changing every little facet. We are happy to splay the fruits of their labor for your enjoyment!
We have confirmed that the iPhone's A4 processor has 512 MB RAM, unlike the iPad's more limited 256 MB. This decision may have been made fairly late in Apple's development cycle, because early leaked prototype phones only had 256 MB.
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You can also take a look at the the YouTube video slideshow of the teardown!
For more detailed technical information on the silicon inside the iPhone, be sure to check out Chipworks' in-depth analysis of the iPhone 4's components.