DVD ROM drives without rip speed limitation rip Single Layer DVD in 4 minutes and Dual Layer DVD in 16 minutes .
Either this DVD ROM has rip speed limitation either you have forgotten to enable DMA ( it is much more likely ) on it or something like this which slows it at reading DVD .
Another instance of the Intel Application Decelerator... Or was it the move to the Promise card that fixed it? By the way, putting optical drives on add-on controllers often causes problems itself. In general it is best to put your optical drives on the motherboard's IDE controller, and leave the add-on cards for the hard drives. They can make better use of the extra speed of the add-on cards anyway.