Generally, if the hard drive interface has a BIOS/CONFIGURATION setup that is performed at a system restart it is considered hardware RAID.
Now, of course, there will always be software involved to some degree. That degree though is often unknown to an end user. You can test it, buy looking at CPU usage and making guesses?
For example, if you setup your system so that it is single drive, (generally RAID 0 with only 1 drive), and watch the CPU during file transfers you can get a base line. Then set your computer up in a mirrored configuration and then do the same process. (I prefer larger file(s) a gig in total size.)
If your CPU usage remains unchanged, your controller likely is doing it at a hardware level. If your CPU usage increases, then it is more software oriented. (The increase should not be all that much.)
Different configurations for different controllers will have different results. (RAID 0, vs RAID 1, vs RAID 5.) There are many controllers that do real well with RAID 0 and RAID 1 and then use large amounts of CPU for RAID 5.
NOTE: This is a pretty course way of getting some numbers, but it's prettty simple. There are more detailed methods to get better numbers.
As for configurations, I like to keep "ALL" of my OS on a single drive. (Boot/System/Paging.)
I, sometimes, will put Paging somewhere else but I haven't really noticed too much of a difference. (I generally, do it when I have used up too much space on Drive C:, or root, and need some back. So often it's just a temporary fix.)
One HUGE problem for Windows 2000, and XP, is that when you are using BASIC disks and have your paging file on another drive letter Windows can become confused. (This ONLY happens when you are moving drives around and rebooted etc.) When it becomes confused it can get to a point where it can't find a paging file and then won't boot.
Microsoft has a workaround for this, but without and emergency recovery disk, I have not been able to get this to work. (And with an emergency recovery disk the configuration would have to be put back into the exact same before it would work there too. Sometimes not something possible of convienient to do.)
Thus, if it's all on the same drive I have NEVER expereinced problems getting things to work again! It's also very reassuring to me to know that only one drive is necessary to get the system up! (Of course you could be tricky as well, and configure everything for single drive operation then make an emergency recovery disk, then move the paging file elsewhere?)
As far as increasing your performance enough to justify the Raptor drives? It's a real hard call. I have been VERY happy with the Raptor drives, and received some of the first ones made. (Back then whey were $300+, so $124 is a real bargain for me.) On my servers chaning ONLY the Raptor hard drives enabled the servers to boot up twice as fast and before. (Although on a 300mhz server that I did just for a test, it had NO affect at all. The server was getting data from the SCSI-2 drives as fast as it could use it anyway, so the Raptors had no affect.)
Did the Raptor drives make everything run twice as fast?
No, just the boot up process but there was a marked increase in performance abliet less than double.
I do think it is safe to say though, that you will not find many people that have purchased Raptor drives that are dissapointed.
A thing that I used to think, that may be appropriate here, is that the optical drive would significantly impact performance? I did some REALLY extensive comparisons on my systems here in regards to that.
While a CD media being recognized causes Windows Explorer to hang, the Windows Desktop, it doesn't seem to significantly affect background operations on hard drives on that same channel. For a long time I had incorreclty surmised that the hang in Windows Explorer during optical media recognition actually caused a slowdown on the IDE bus. (Different motherboards may produce different results.) Reading optical media did cause a slight slowdown on hard drive transfer but that was less than I expected as well.
You can always start out with one Raptor and we what happens?
Most people don't mirror their drives, and just rely on backups. That works, I don't change the software on my system too much, so having crashes due to software configs is pretty much a mute point for me. So, for me, that basically leaves hardware failures.
Another thing I do, on certain systems, is to mirror the Boot/system drives but really only use it as a restore point.
Configure the system for RAID 1, mirror the drives. Then I break them mirror and use the offline drive as a backup/restore point.
I add software, change configurations, etc. If all still works well I remirror the offline drive to the online drive. Otherwise I revert to the offline drive, and start over.
Hopefully not too long for you, and helpful?