I've been experiencing extremely slow disk writes in Windows Vista, using an Intel Matrix ICH8R RAID-5 array on an Asus Commando motherboard.

Files were transferring over my gigabit network at 2MB/second. At first I thought the network might be blame, but sending files from Vista to Linux is much quicker, with network utilisation hitting 40% or more, compared to perhaps 2% when I'm syncing Offline Files.

Reading that the early Intel drivers were quite poor, and that I might actually have been lucky to get Vista to install onto and boot from a RAID-5 array in the first place, I upgraded to driver version 7.5.0.1017 complete with a utility called Intel Matrix Storage Console. Using the console I was able to verify that all of the drives report themselves as healthy, and turn on write caching. Using another Intel tool called IOMeter, I was able to test write speeds, and this returned around 15-20MB/s, which is pretty woeful. Curiously, Vista rates my system at the maximum 5.9 for IO reading. I appreciate that RAID-5 writing is slow, but it shouldn't be this slow surely?! I've been spending days just trying to get my data (which includes a lot of my CD and DVD collection) synced up...

Given that the new driver hasn't helped much, I've been starting to wonder if I have a hardware problem. At least one of the drives (four Seagate 7200.9 500GB drives, 2 of them new, 2 of them 6 months old) is extremely noisy - noisy to the point of being irritating. Despite living in a quality case and being seated on rubber grommets, the thing is rattling away like mad and hardly the silent HTPC I'd hoped for. The Linux box, by contrast, is near silent, despite containing 5 discs, some of them quite old. In addition to the noise, the case is throwing out a huge amount of heat, and most of it seems to be eminating from around the drive cage.

Exhausted and frustrated with Vista, I thought I'd give Kubuntu a shot. It's been many years since I tried Linux on the desktop, and I figured too that I could perform some write tests under Linux (and perhaps get my data shifted at the same time!). If it was significantly faster under Linux, we can blame software; if it's slow there too, I'd have to investigate the hardware. Hell, I might even like it so much that I'd ditch Windows in favour of VMWare!

So, I boot into Kubuntu and what do I see? Four seperate hard disks. It seems Linux doesn't yet support the onboard RAID solution supplied with millions of hobbyist motherboards. Sigh. What next? I could take the array apart and test the disks individually, but I don't have enough storage space on my Linux RAID array to take all the data!