There seems to be several versions of DV-W28E drives depending on where you live…
Can’t find a manual for RAM drive right now though.
SCASI standard connection should be the same no matter what brand of drives we are talking about (pin assigment numbering).
But before you begin ironing anything, we have to try get your drive to work in UDMA mode.
Have you tried to enable DMA in bios and/or in XP?
I have the similar experience from my sons laptop (CompaQ Armada M700), with a PIII-750 mobile. Originally a DVD-ROM was installed. Then I bought a NEC ND-6650 and swapped the drives. After install XP emediatelly recognized the DVDRW drive and run it in UDMA-2 mode from start.
Out of this I think you have to check if your laptops motherboard is able run in DMA on secondary channel at all. A visit to IBM support might give you some hints.
BTW, Armada is equiped with Intel 440BX/MX chipset.
Sorry if I can’t give you a definitive answer right away.
Please keep us posted about your progress.