Rumours are circulating that the next-generation iPhone will feature a 3D graphics chip, which would allow the device to support far more advanced games. Next week Apple are to unveil a new edition of the iPhone at the company's annual World Wide Developers Conference, reports Kotaku. The website claims that a source has informed it that forthcoming version of the device will include a built-in 3D graphics chip, operate on a new, higher-speed network, and be hit retail in mid-July.