MacRumors has confirmed that the upcoming iPhone 4 will ship with 512MB of RAM -- twice that of the iPhone 3GS and iPad. The post notes that the iPhone 2G and 3G packed 128MB of RAM, while the iPhone 3GS and iPad ship with 256MB.
It's believed that the lower RAM footprint in the original and 3G iPhones is the reason why Apple isn't supporting multi-tasking on those devices in iOS4. Apple isn't supporting the RAM-hungry iMovie app or its breakout video calling service, FaceTime, on any device other than the iPhone 4.
What's more surprising, perhaps, is that Apple intentionally suppresses technical details of the iPhone:
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.
Apple confirmed the 512MB figure during WWDC last week in a session video (147, Advanced Performance Optimization on iPhone OS, pt 2) which is now available to registered Apple developers.
Nice catch by MacRumors and a nice little bonus for iPhone 4 customers.