Sapphire Radeon HD 5670 Ultimate not as good as onboard graphics?

[sadsapphireowner]

Recently attempted to upgrade from onboard Radeon HD 3200. My setup:
Gateway LX6200-01
cpu: amd phenom x4 2.2 ghz
ram: 8 gig ddr2
os: Win 7 64
3t of hard drives
stock 400W power supply
stock HD digital tuner
Primarily a media center PC. Wanted some additional power for video processing and to enable smooth video via DirecttvtoPC. With one available PCIe 2.0 slot available and a big case (and large case fans), I thought this card would be perfect. It is everything I thought it would be (quiet and cool) EXCEPT that it won't render smooth HD video from my tuner card. Video is choppy. The onboard graphics had no problem with this task.
I used the AMD Catalyst control center to remove all previous drivers, disabled the onboard graphics in BIOS, and installed latest CCC. Everything I read on this indicates I should see much better performance. Any ideas?

 

[clarkx100]

Wait, a 400W power supply? That may be your problem right there. The 5670 is by no means a High End gaming card but it should do HD video like a champ. You may need to get a stronger Power supply.

 

[iam2thecrowe]

there is no point upgrading to a better graphics card for HD video. Even the lowest end 5450 decodes HD video no different from a 5850. Sounds like the problem is whatever particular codec the HDTV tuner is using is not compatable with the accelleration the 5670 provides. If it was working fine before, why did you install a dedicated graphics card?

 

[adam_x_brookes]

No it's really not the power suply 400watt is more than sufficient to run that card. Could be a faulty card, try getting it exchanged for a new one? X

 

[sadsapphireowner]

Thanks for the feedback, all. I was about to take Adam X's advice and get an RA, when I decided to try wiping drivers (again) and re-installing one last time. The only thing I changed was that I downloaded the CCC from Sapphire instead of AMD, and voila, everything works! Same releases on the drivers--maybe just slightly different versions? Don't know. Anyway, Windows graphic experience went from 3.4 to 7! OTA HDTV looks great, ESPN 360 never looked this good, smooth HD video over Netflix--still need to try the DirectTVto PC. Overall, very happy--guess I'll have to change my user name! Sorry to take up space and time here needlessly. Thanks again for the comments!