"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
iPhone 4 Confirmed to Have 512MB of RAM (Twice the iPad and 3GS)
Since the launch of the original iPhone, Apple has made efforts to hide some of the actual tech specs of the device from consumers. Apple has never advertised or even published the processor speed or amount of RAM found in the iPhone. Arguably, Apple is trying to shield customers from these technical distractions and instead trying to focus on overall functionality.
More technically inclined customers, however, still love to know what they have to work with. The original iPhone and iPhone 3G contained 128MB of RAM, while the iPhone 3GS was boosted to 256MB of RAM. Similarly, the iPad contains 256MB of RAM. This discrepancy offers a technical explanation why Apple is not supporting iOS 4 features such as multi-tasking on the original and 3G iPhone -- there simply isn't enough RAM.
We have since heard that the upcoming iPhone 4's RAM has again been upgraded. This will bring it to a total of 512MB of RAM, twice as much as the 3GS and iPad. This number actually contradicts tear down photos of a prototype iPhone 4 that was leaked to the internet. An analysis of that prototype device showed it only carried 256MB of RAM. The 512MB figure, however, does agree with a Digitimes report from May 17th that confirmed a 960x640 screen resolution, thinner display, and indeed 512MB of RAM. We had heard that Apple confirmed this 512MB figure during one of the WWDC sessions last week, and have now verified this. The session it was revealed in is now available (Session 147, Advanced Performance Optimization on iPhone OS, pt 2) for registered Apple developers.
The added RAM should help overall performance and multi-tasking on the new iPhone 4. It could also explain why the iMovie App that Apple introduced at WWDC will only run on the iPhone 4. Apple has said iMovie will only run on the iPhone 4 and not the 3GS or even the iPad. It seems conceivable that it actually makes use of the extra RAM offered by the iPhone 4.