CPU usage at 10%, in conjunction with an AMD Duron 650 under Windows XP.
The use of the hardware accelerator makes a noticeable difference, especially with older PC systems with less CPU power. The system we used in our tests with an AMD Duron 650 exhibited an average CPU load of 80% - i.e., when using the media player from Microsoft under Windows XP and a special MPEG-4 test sequence. By using the decoder board, the processor load fell to an average of 10% to 12%.
The EM8475 Decoder Chip's Mode Of Operation
Schematic diagram of the EM8475 decoder chip.
The graphic illustration above schematically depicts the structure of the MPEG hardware decoder from Sigma Designs: essentially, the board is based on the EM8475 chip from Realmagic - a highly integrated DSP processor for MPEG decoding. The chip also contains the PCI controller and the control unit for the memory interface, the board with 4 MB cache memory being equipped with 7 ns access time. The memory clock speed is 133 MHz.