Enabling ultradma mode 4 for 160p6s

I have a liteon 160p6s dvd burner as secondary master.The current mode for this drive is ultra dma mode 2.I know that it is capable of udma mode 4.I am using a 40 conductor cable.What should I do to make the burner interface udma mode 4? Do I need a 80 conductor cable? Please provide instructions.
The OS is xp sp2.And the chipset of mother board is capable of udma mode 5

Hi,

in order to enable UDMA 4, an 80 wired IDE cable is required. Using a 40 wired cable will result in max UDMA 2.

Michael