Originally Posted by jcrandall623
Ok, BUT... My raid 0 will still basically almost double my HD speed, right? Even though it's slow, and raid is meant to be fast, it'll still be better for my current system. Is this correct?
This is a common misconception - RAID0 for many tasks is no faster than single drives. RAID only helps sequential performance, and your OS actually does very little of that. It does nothing for small random transfer performance, and can even slow it down over a single drive. Which means that even in RAID0, your older, slower drives will perform worse in day to day usage than single, more modern drives. When you run a sequential benchmark you will likely get similar speeds (~120MB/s max), but the IOPs rating of the array will likley be much lower than on a more modern single drive, and thus the 'snappiness' and general feeling of the computer in use will be worse.
There is also the problem of drive failure - running 2 old drives in a non-redundant array is asking for trouble without a backup, because if either of them fail (and remember they are getting old, and you have no idea what stress your 'new' drive has been through if you do go the 2nd hand route) you will lose all your data. As a result you should really have a full backup - which means buying a second extra disk, and therefore means spending the same money as you would need to buy a faster drive in the first place. So it just isn't worth it.