Nvidia upgrade issue - choppy sound and video

[Gary Waters]

Hello,

I am using Fedora 12. I just upgraded from an nvidia geforce 6200LE 
512MB to an nvidia geforce 8400GS 512MB ( PCI-X ). All video and sound 
"jumps" and is quite choppy. When I switch back to the 6200LE everything 
falls back into place. I decided to update to the latest nvidia driver 
and have the same issue. The 6200LE works fine, whereas the 8400GS has 
the sound and video issues. The card works fine in windows 7. It also 
seems to play youtube videos well in firefox ( Linux ). Any 
suggestions/solutions would be appreciated.

Gary