There is a signal processor in the iPhone 4 A5. Phil Schiller mentioned it briefly in the keynote when talking about the camera (64 mins in). Schiller referred

There is a signal processor in the iPhone 4 A5. Phil Schiller mentioned it briefly in the keynote when talking about the camera (64 mins in). Schiller referred to it as an "Image Signal Processor" so it may be that it is custom silicone for used only by the camera but it seems more likely that it is a more general DSP and was badged like this for the presentation. It is probably a version of ARM's NEON technology: http://www.arm.com/products/processors/technologies/neon.php http://www.arm.com/products/processors/technologies/neon.php NEON technology can accelerate multimedia and signal processing algorithms such as video encode/decode, 2D/3D graphics, gaming, audio and speech processing, image processing, telephony, and sound synthesis by at least 3x the performance of ARMv5 and at least 2x the performance of ARMv6 SIMD Which directly mentions both image processing and speech processing. Update: According to wikipedia that's exactly what it is: http://en.wikipedia.org/wiki/Apple_A5 http://en.wikipedia.org/wiki/Apple_A5 The A5 contains a rendition of chip based upon the dual-core ARM Cortex-A9 MPCore CPU with NEON SIMD accelerator and a dual core PowerVR SGX543MP2 GPU. Their source is the reliable AnandTech: http://www.anandtech.com/show/4216/apple-ipad-2-gpu-performance-explored-powervr-sgx543mp2-benchmarked http://www.anandtech.com/show/4216/apple-ipad-2-gpu-performa... Also, the corresponding A4 page makes no mention of NEON or DSP: http://en.wikipedia.org/wiki/Apple_A4 http://en.wikipedia.org/wiki/Apple_A4 Interestingly, as this is the iPad A5 being discussed it strengthens the argument for Siri-on-iPad2 (assuming the signal processor is key to Siri working efficiently).