Referring to the question that was asked awhile back, DSD is the name that Sony uses for their method of PDM (pulse density modulation) as opposed to the typical PCM (pulse code modulation). CD is 16-bit/44.1kHz. SACD is 1-bit/2.8224Mhz. DSD is far more capable than 16/44 CD audio with its 22.05Khz hard cutoff, but against high-res PCM, the argument is trickier. SOME people think that DSD sounds much closer to analog than even high-res PCM, but as with everything, the mastering is far more important than everything else.
We are going to have an article about this soon on Metal-Fi.