A raid is simply a way of formatting a group ( 2 or more) of physical hard drives together so that they appear as a single logical drive. The result increases the read and or write speed and in some cases gives redundancy in the event of drive failure.
However there are several ways of creating the raid which offer different levels of speed and redundancy.
Some types of raid can be set up simply using software, ie the drive utility can create them. Others need a hardware raid card to manage the data and is probably the better option rather than a simple software controlled raid.
I am UK based and have used these guys https://www.rentaraid.co.uk the site gives you loads of options and info. I am sure you can find the same products wherever you are.
Raid 0 is the cheapest and simplest option, requires no raid card and gives read/write speed increases however beware as it offers no redundancy so if one drive fails you lose everything across them all.
Probably want to look at a Raid 1 or Raid 5 setup
Obviously if your Mac supports Thunderbolt then that is fast enough as it stands.
[Robert Floutier] “Now looking at render issues, am I right in believing that the render files are stored on a harddrive and that FCP only allows a certain amount before it gets full and slows down rendering to the point when it will not allow rendering”
Your render files are saved on the drive you assign as the scratch disk which is in the system settings. You would set your external drive or raid to be the scratch disk. Obviously you can only store media/renders to the capacity of this drive/raid. Its never a good idea to fill it totally. Try to leave at least 10% free or your system will slow down regardless of the speed of your drives/raid.
best wishes
Neil
http://www.patience.tv