on My AMD K6-2 333mhz. I don't need a Decoder Card.
it play Smooth DVD with with ATI Graphic Card, and Power DVD which has 3D NOW Support
Running the most intense scene on my ATI rage128 is around 75% - 89% cpu usage.
On the entire movie as a whole, it hovers around $25% - $50%.
However, on NONE-ATI Graphic cad like Savage S3, I got 100% cpu usage with choppy frame rate
In short, CPU is good enough - but is your Graphic Card good enough
ATI has the best hardware Motion Compensation that cuts down the CPU requirement.