What version of the firmware are you using?
With A104 the max speed for the Prodisc F02 is 4x, changed in A105 & A106 to 16x.
However, that's for a GSA 4163B , not a GWA 4163B. So I'm not sure what happens about flashing to these versions, maybe the Dell site has something.
Another however, this should not make burning so slow. So are the burner & HD on the same IDE cable or separate ones. If on the same one then burning will be pretty slow anyway.
The other things, when you say DMA is enabled what is actually showing in the Current Transfer Mode box?