When ATI gives you a warning about DMA not enabled for your hard disk, just remove the IDE controller: in My Computer's Properties(right click), Hardware, Device Manager, IDE controller, Primary/Secondary IDE, uninstall (right click).
It will want to restart, and after that it will reinstall the driver back on. DMA should be back.
To check status of DMA or PIO mode, follow the same procedure but don't uninstall, it's in the property settings of the IDE controller.
Took me 2 days to find this solution, thanks to google. (Keyword: "force dma").
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