20A4P Problems?

Bought a new drive. For some reason it’s burning 16X media slightly slower then my old TDK is burning 8X?

I’ve tried many things. Even tried the overspeed thing. Burning 8X media at 8,12 and 16x it takes about 7 minutes 10 seconds?

Burning 16X at 16X I get 6:41. Burning 16X at 20X I get 8:45.

Not good. File I’m burning is 3600MB(3.54GB). Drive is slave on secondary IDE. Primary is a read only drive.

Any help would be appreciated.