Well, the gain you get depends on which kind of RAID array you use. RAID 0 is called data striping; instead of writing to one drive, the data is split and you write to two drives that are synced at the same time. This effectively -doubles- your hard drive read/write bandwidth. The down side is RAID 0 has no fault tolerance whatsoever; if one drive fails or the data gets corrupted, there is no recovering. Replace, recreate the array and reload is the only option.

 

RAID 1 is data mirroring; you write the data to two drives simutaneously. Instant backup, so one drive can crash and the other will pick up the load with no noticeable delay. So long as one drive is intact, it is just replace the bad drive and recreate the array, copying the data on the still good drive over. This is the version that many use for data safety, and you get no speed increase out of it.

 

 RAID 5 uses 3 drives; two data drives and a parity drive. You get some of the speed increase, and if you have a replacement drive at the ready, you can lose a drive and rebuild it from the data on the remaining two drives. Not really used much outside of server application.

RAID 10 is a combination of mirroring and striping. You get both the speed and data redundancy, but you have to have 4 identical drives in the array. One drive can fail with no problem, so long as you replace it before another drive goes. 

 

 There are many, many other kinds and numbers, but those are the basic kinds, and the others are all built on these (mainly done so the maker can claim propietary rights to their RAID 26 uber array with coffee holder built in!).

 

When you get ready to upgrade, be prepared to hunt. Most of the audio cards out there are more gaming cards than audiophile, and a lot that boast a breakout box either prove unavailable, or are like the Creative X-Fi Titanium, where the box only has a couple of RCA jacks (no MIDI, no optical, no preamp controls, etc). The bloody audio codecs on the motherboard are good enough for the masses (despite the hit the CPU takes doing the audio processing), so =good= sound cards are getting harder to find....