After installing the chipset driver, you should install the IDE driver from the chipset manufacturer, if this driver wasn't installed together with the chipset driver. Just open the Hard disk controllers key and check if the driver listed is a generic type or specific for the chipset available on your motherboard, as we show on Figure 6.

Figure 6: IDE driver correctly installed.

After that you need to open the hard disk properties and check the DMA box available to enable bus mastering. Open the Disk drives key and double click on your hard disk, which may be listed as "Generic IDE Disk Type 47". On the window that will pop, click on Settings tab. Check the DMA box, as shown on Figure 7, and then click on Ok to enable bus mastering. If you don't see a DMA box, this can mean two things. First, the bus mastering is already enable thru the IDE driver from the chipset manufacturer. Usually when this is the case, your hard disk manufacturer and model will be listed on the Disk drives key instead of "Generic IDE Disk Type 47". The second possibility is that the IDE driver wasn't installed. Anyway, you can check if the bus mastering is or isn't correctly enabled using HD Tach software already mentioned. This is the best way to determine if the bus mastering was correctly enabled or not. Pay close attention to the CPU utilization, if it is below 10%, the bus mastering drivers are installed. Otherwise, they aren't.

Figure 7: Enabling Bus Mastering.