Interesting to hear Asus promoting the use of the Promise SATA controller. It's jammed onto the PCI bus along with your PCI slots, your gigabit NIC and your Firewire chip. If it were the only thing getting action on the PCI bus, then sure, it may not make much difference.
But the VIA SATA controller rides "above" the PCI bus, on the higher-bandwidth V-Link that links the northbridge and southbridge. That leaves more headroom for the array to "sprint," which is the main attraction of ATA RAID0 in the first place, and also leaves that much more PCI bandwidth for PCI stuff to use. Maybe I'm making a mountain out of a molehill, but if you plugged in a Firewire DV camera and started hammering lots of data around doing video editing or something... yeah. It could be slower than it needs to be.
Other than that, I was aiming for the VIA SATA controller because it sounds like the array is already there, ready and waiting for WinXP to get a clue and use it for Setup. The VIA SATA plugs are the ones marked SATA1 and SATA2, while the Promise SATA is PRI_SATA and SEC_SATA, the lower pair that sit side-by-side.
If you do swap controllers then you'd want to redefine the array. You could stick with the same controller, delete the array and re-create it if you think there's something wrong with it, but my guess is that you are simply not getting Windows Setup to see the controller itself, and therefore it has no way to get to the array. If you do give it the VIA SATA controller's drivers on floppy, what message does it give when it gets to the point where it halts?
