Guys, First off, The "hardware" RAID controllers that the vast majority of you are using are *NOT* true hardware RAID; they're "firmware" RAID or simply put it's software RAID done in a BIOS chip of a cheap motherboard controller. There is no performance difference between these motherboards and software RAID, as all of the work is done on the CPU in either case thru a driver. If you want server-like performance you'll need an actual PCI RAID card for about $100-$300 depending on how fancy you want to get about it. Next, a little about software RAID, which does dramtically increase disk performance and overall system performance for any OS; the reason mainly being that any time your OS needs I/O from the swap file it normally has to wait, oh, 2000 or so clock cycles to get to that data. That wasn't a complete sentence, but anyway, software RAID (or firmware) is implemented in a driver for the OS. The problem with this is Windows has to boot up and load this driver first before ANYTHING on this RAID volume/array can be accessed. In nix's (Linux, Unix, Solaris, BSD, whatever), this isn't a problem because all the bootable stuff is on a non-RAID partition, and the actual kernel, modules, init stuff, etc. can be accessed after the OS loads the raid drivers. In windows, a.k.a. your issue daveo, this is not the case. Microsoft calls the part of windows that actually does the booting (ntfs.sys, ntdlr, NTDETECT, boot.ini) the "system volume," and the rest of the stuff under Windows\system32 the "boot volume." It's confusing; I know. Usually they are the same thing C: but this doesn't have to be the case. Read on here: http://www.microsoft.com/resources/documen...stem_volume.asp (Yes, that's all one line). It applies to server 2003, but should work for XP Pro as well. RAID 1 makes two simultaneous writes to each disk everytime you write a file. It's fault tolerant, meaning if one hard disk fails you can replace it with the same model and be back up and running again in an hour or so, by copying the contents of the other disk onto the new one. It also makes for significantly faster disk reads because the driver reads half the blocks of data from disk 0 and the other half of the blocks from disk 1 AT THE SAME TIME. If you follow the instructions above that is the ONLY way to get a bootable software RAID setup in Windows. Firmware RAID has the (small) advantage that Windows can pretend that it's hardware raid and put the driver into a small un-RAID'ed part of the disk, usually at the end or right after the MBR and partition tables. This way, you don't do the Microsoft software RAID, the driver simply makes call to the BIOS on your motherboard's RAID chip. Hope this clears it up a bit, xiphias