Did a search on Dell Dimension 9100 and seems some DID come with RAID already set up as a default.
But as it is RAID 0 is one disk crashes you lose all the data on both disk, SO BACK UP QUICKLY.
See this web page
http://reviews.cnet.c...9100-review-39192184/
Text says:
"One of the more interesting inclusions in our 9100 was two 160GB hard disks set up in a RAID 0 (also known as 'stripe') configuration. This treats the two drives as a single contiguous hard disk, switching between the two while writing a stream of data. In theory, this increases the speed of your hard-disk activity because two drive heads are skittering across the platters at the same time. In practical terms, you might see a drive performance increase of around 30 per cent using a RAID 0 array. On the downside, because data is split almost at random between the two disks, if one breaks down you effectively lose all your data on both disks"