The Samsung chipset at the heart of the iPhone utilizes a 32-bit RISC ARM processing core, the ARM1176JZ(F)-S. The ARM device is capable of running at 620MHz, but Apple has downclocked it to 412MHz, presumably in the interest of extending battery life. (Apple has, at least once in the past, adjusted the clockspeed of both the processor and the system bus via firmware update.)
The Samsung SoC also features an implementation of Imagination Technologies’ PowerVR MBX Lite 3D accelerator, likely running at the iPhone’s bus speed of 103MHz. This fourth-generation PowerVR chipset is basically an evolution of the second-generation graphics hardware used in the Sega Dreamcast (an amazing console, to those unaware) and which, like its console predecessor, utilizes a unique tile-based rendering system.
The MBX Lite is capable of providing fill rates exceeding 135 million pixels per second and a throughput of 1.7 million triangles per second, depending on configuration.