DMA won't enable on any hard drive

[xmrkite]

OK, when i run that command i get:

The command "metacity --replace" failed to run:

Failed to execute child process "metacity" (no such file or directory)


Please remember, i'm using mythbuntu which uses xfce and not gnome.

[xmrkite]

OK, i added in an sata hard drive, and when playing videos from that drive, i get the same stuttering, so it probably isn't dma, but it's gotta be something.

Are there some sort of tests i can run to find out where the lag is?

Thanks