Meh, I did a quick search and this is what Canon says about the current digic 4 processor:
The performance of a digital camera is largely determined by three key components: the lens, the image sensor (CMOS or CCD), and the image processor. The image sensor, which takes the light entering the camera through the lens and converts it into electrical signals, can be compared to the film used in a traditional film camera, while the image processor "develops" the image. If any one of these three components is of substandard quality, it will negatively affect the images that the camera produces. Canon, which has been making cameras for over 70 years, develops its own lens units and CMOS sensors in-house, and has for some years now also been designing its own image processors: the DIGIC digital image processors.
The evolution of the DIGIC image processor has been the result of an ongoing search for higher and higher levels of image quality and faster speeds. DIGIC 4, which Canon began using in its camera products in the fall of 2008, represents the sixth generation of DIGIC processors. Compared with first-generation DIGIC processors, device performance has improved 50-fold in the space of just 10 years.
Today's DIGIC image processor does more than mere image processing: It controls a wide range of functions and circuits, including automatic exposure control, exposure mode control, image file compression/playback control, LCD display control, and more. All of these functions are contained in a single-chip system large-scale integrated circuit (LSI), and the same image-processing platform can be used in any Canon digital camera, including the Digital ELPH/IXUS and PowerShot series of compact digital cameras, and the EOS digital SLR (single-lens reflex) camera series.
One could say that DIGIC is the "brain" of Canon digital cameras. DIGIC 4, the latest version of the DIGIC digital image processor, provides dramatic improvements in terms of image quality and processing speed. So how have these advances in processor design been achieved? We talked to four members of the DIGIC 4 development team to find out more.
** On the digic5 press release I vaguely remember a key note at reduced noise... Canon claims in the above statement that the digic processes the image, hence controlling the noise... So it make perfect sense that the digic, if you take the statement above at face value, that the digic controls the noise better than the intel computer in this regards.