Hi
Raid setups have tradeoffs, usualy in one of two ways. Either you can have more space with less reliabilty (raid0), or less total space with more reliability(raid5), total number of drives for each being the same.
My game system, for example, has 2 10000rpm scsi drives and a hardware raid controller, they work pretty well together in aid0, but don't really give the performance expected in many cases. Raid, of most any type, will never give the lowest disk access times, wich is what everyone should really be concerned with rather than transfer rates or any other criteria, no lie. If I benchmark the array with iometer or hdtach, it benches quite a bit slower than if I benched with atto or sandra, iometer and hdtach being more "real world" and less "hopefull" than atto or sandra, I have given up 4ms access time to get an aid0 array with two times or more access time, easily measured. 8ms might as well be forever to a computer. Ok more to the point, raid is something that in my case can fail on me quite easily, one drive fails and the whole thing is gone, and it does not have double the performance of each drive individualy. If you do a raid1 with your two (or more) drives, you will get slightly better reads, probably slower writes, but you now have half the disk space. If your data is that valuable there's your answer, do raid1 if you can, but I prefer disk space over the unavoidable risk of data loss we all face.
What should I have done to maximise disk space rather than aid0? Just run both disks without any raid at all, one devoted to the os and storage, and the other for all the apps/programs, with a pagefile on each drive. The reason one might want pagefiles on each disk is because windows, and Linux for that matter, can write to one drive's pagefile while it reads from the other. Or vice versa. Write to both, read from both, whatever. This is beneficial in all sorts of ways. As well, having one disk more or less dedicated to the demands of the os while the other disk attends to apps reduces disk latency and disk subsystem contention further. Systems set up this way run very smoothly.
I will say this about raid stripe sets, if you do video editing or work with generaly huge files, aid0 can be of benefit if you don't mind the risk of data loss. I say aid0 as the 0 level has no redundancy. If you just use the system to browse, play games, burn cds, etc, you will be far better served by running those two drives as I have stated above. Much more reliable this way. Now on to another aspect of raid technology: most all onboard (non-scsi) raid chips, and most (non-scsi) add on pci cards use the cpu to perform all their functions, your cpu has to do all the work. My raid card has it's own cpu, memory, and os (more or less) to perform all those disk functions. Now if you have a super-powerfull cpu you don't have to be too concerned with this cpu usage, but it is there, all the time.
But no matter, do as you like. You can always learn from trying various raid levels and whatnot, I am certain, though, that you will find things pretty much as I have laid them out to you. But most people, me included, will be better served by running the disks separately, not part of an array. I intend on reconfiguring my drive system as independant disks, no array at all. Giving up lower access time just to have an aid0 array isn't really worth it when all I care about is games. In the games I play, latency is everything.