Combined with a new hard drive and a cd burner, the following settings gave a push to disk performance in XP.  I noticed the biggest improvement in Cool Edit, Sound Forge, and Nero, three audio apps that really know how to say thank you when they get the speed they need:
    - Open My Computer, right-click the letter for your hard disk, choose Properties
    - Click the Hardware tab, select the name/model of your hd, click the Properties box in the lower right corner
    - Choose the Policies tab, make sure there's a checkmark next to Enable write caching on the disk, and click OK twice to exit all the panels.  If you have other types of drives (like SCSI), other options will be available.  The rest of mine are grayed out.
    - Right-click My Computer, choose Properties, Hardware tab, Device Manager button (middle right, top right in SP2)
    - In the list, look for IDE ATA/ATAPI controllers
    - Right-click Primary IDE Channel and choose Properties
    - Click the Advanced Settings tab and select DMA if available as the Transfer Mode for devices listed, then click OK
    - Back in Device Manager, do the same for the Secondary IDE Channel

More on DMA:
    - (Real Knowledge) DMA: what it is, how to enable it for Windows 98 / ME / XP