Keeping the Cell CPU out of pixel shaders, for the most partGameSpot has translated an interview with Sony Computer Entertainment president Ken Kutaragi, originally posted at Japanese tech wire Impress PC Watch, which touches base on many technical aspects of the PS3 architecture.
Kutaragi reaffirms Sony's support of Nvidia, as he explains that the companies will continue working together so long as their philosophies concerning GPU (graphics processor) design remain on the same path.?This means that they are interested in perfecting the art of programmable GPUs and shaders, allowing the potential for RSX graphic capabilities to be improved over time by Nvidia/Sony engineers.
He also clarifies Sony's decision to equip the PS3 with a separate, graphics-specific processor (Nvidia's RSX, reportedly based on their forthcoming G70) as opposed to simply using another PS3 Cell processor for a GPU:
"The Cell's seven Synergistic Processor Elements (SPE) can be used for graphics.?In fact, some of the demos at E3 were running without a graphics processor, with all the renderings done with just the Cell. However, that kind of usage is a real waste. There are a lot of other things that should be done with the Cell. One of our ideas was to equip two Cell chips and to use one as a GPU, but we concluded that there were differences between the Cell to be used as a computer chip and as a shader, since a shader should be graphics-specific."
It should be noted that part of the reason the Cell was running without the RSX during the E3 demos was because Nvidia didn't actually have the RSX ready yet.?This PS3 GPU has yet to enter mass manufacturing over at Nvidia in fact, though its specs have been made available already.
The ultimate goal is to have the PS3 render real-time 3D graphics in an equally real-time 3D environment, and Sony believes this can be achieved by sharing data which travels both ways between the Cell and the RSX GPU.?Because the PS3 is expected to support two HDTV screens running at full resolution (1920 x 1080 pixels each), the RSX will require its own memory separate from the Cell's.
Kutaragi does touch on the PS3 backward compatibility as well, revealing that this will be done using a combination of both PS3 hardware and software capabilities.?Hardware assistance is required because of a few snags in achieving thorough backward compatibility through PS3 software solutions alone.
Article Link: GameSpot
