I think your calculations are way off. Where are you getting 34w for the p4600...a system with that processor should idle at 20-25w all in (assuming a single drive)..the p4600 likely uses close to zero at idle as its integrated into the processor. I dont know how the hardware acceleration will be implemented, Nvidia might be a complete waste. Benchmarks dont paint a complete picture. I would wait until its released then buy the card and test, so you can return it if it doesnt help.