Any suggestions as to the best way to investigate I/O would be much appreciated.
Perhaps someone with XP can suggest the best way. In Vista (yes, I know you hate Vista, I find it works great), I use the Reliability & Performance tab in Computer Management. Here's a typical disk-churning episode, where the MyLog journal is having a series of large re-writes. Whilst this is happening, my PC becomes slow to respond as well.
![](http://farm3.static.flickr.com/2526/3880800434_3544e91a62_o.jpg)
A good place to start is right-click the drive that RB is installed on, and select Properties. Check whether the drive is compressed or indexed - indexing can be a real I/O hog.