HD 3850 vs ASUS M2A-VM HDMI 690G for HDTV?

Hello.

I currently own a ASUS M2A-VM HDMI 690G with 2-GB RAM, AMD 6400 3.0 ghz. I'm using it to run my Xbox HD-DVD addon through my computer into my Denon 2307C HDMI receiver onto my Sharp 46" 62U LCD TV Through HDMI.

Currently when playing HD movies my CPU is at around 50% and the movies always stutter and my machine can't get up. I have 1GB allocated to the onboard Video thinking it would help but doesn't.

I see that HD 3800 series cards have Avio and HDMI which is great.

Will buying an HD 3850 or 3807 (whichever is better and can do it) take the stuttering out of the movies and reduce the CPU usage significantly?

Or should I just invest in another 2GB of RAM and hope for the best?


Thanks

S