I have the same motherboard, and use two Maxtor 40-Gig, 7200 RPM drives in a RAID-0 configuration. I also set it up as a dual-boot system with WinXP and Win98 SE. Setting up the RAID array is simple, just read the MB's user's guide and activate the appropriate set-up menu (using control-f, I think) during the boot sequence. Setting up the dual-boot configuration is also painless; just use Fdisk (or a comparable program) to set up multiple partitions on your disk (or disks, in the case of a RAID array), and install Win98SE first. I set up my WinXP partition as an NTFS file system, which has some advantages (e.g., encryption) over a FAT-32 system. If I had to do it over again, however, I think I would make both partitions FAT-32 so that I could freely transfer files back and forth. As it is, my WinXP installation can access files in my Win98SE directory structure, but not vice-versa.
Using the RAID chipset on your motherboard, you can configure two identical drives as a RAID-0 array or as a RAID-1 array. A RAID-0 array offers a performance advantage (over either of the drives configured as a stand-alone drive) because of the way that it stores data in alternating "stripes" on the two drives. I canont quantify the advantage a RAID-0 array of two 5400 rpm drives would have over a single 7200 rpm drive, but I don't expect that it would be extreme. Moreover, a RAID-0 connection of two n-byte drives yields an array of size 2n bytes (e.g., your two 80 GB drives would form a 160 GB RAID-0 array). A RAID-1 array offers no performance advantage, and a RAID-1 array of two n-byte drives yields an array of size n bytes (e.g., your two 80 GB drives would form an 80 GB RAID-0 array). The advantage of a RAID-1 array is that it uses data redundancy so that the failure of either of the two drives should be (I have not used a RAID-1 array) recoverable.
From my experience with RAID-0 arrays on two different motherboards, there are (at least) three problems or potential problems of which you should be aware before going down this road. You'll have to decide whether those problems are worth the modest performance gain.
First (and this applies to either RAID configuration), you will not be able to unplug your two RAID drives and connect them to another motherboard (unless it uses the same or a compatible RAID controller) if you decide to build a new PC, upgrade, tranesfer data, etc. If you use a single, EIDE drive, you will have much greater flexibility in that regard.
Second, RAID-0--the only configuration that gives you increased performance--offers no increased protection against drive failure. To the contrary, if you use RAID-0, if either of the two drives fails, you are likely in an unrecoverable situation (i.e., the probability of an unrecoverable failure is GREATER for a RAID-0 configuration than it is for a single drive). A RAID-1 configuration uses data redundancy, so that if one drive fails, you should be able to recover. I've never tried this on a PC with two drives, so I don't know how well it works. RAID-1, however, provides no performance advantage and your two 80 GB drives would yeild only 80 GB of storage.
Third, it is a bit of a hassle getting the operating system installation programs to recognize the RAID array, which you set up (define the array, its partitions, and format) prior to installing the operating system. If I recall correctly, use must use a utility on the ASUS driver CD-ROM to create a floppy disk containing the RAID drivers. The WinXP set-up routine will prompt you for this disk during installation. It is no big deal, really, but if you don't have a working PC on hand on with which to make the required floppy, it can be frustrating.
If I were in your situation, I would create a dual-boot system, placing the Win98SE installation on one of the 80-GB drives and placing the WinXP installation on the 100-GB drive. Even though I have a dual-boot system, I almost never use Win98SE, so placing it on the 5400 RPM drive would be no big deal. In particular, I play AH under WinXP, and find the performance to be as good, if not better, as under Win98SE.
(If, by chance, your reason for installing Win98SE is to use a Saitek X-36 or X-45 rig, you can use it under WinXP with drivers available from
http://saitekhelp.simhq.com. Those drivers are, in my opinion, superior to Saitek's SGE solution under Win98SE.)
Hope that helps.
- JNOV