Options : Enabled, Disabled

This option enables you to activate/inactivate the first IDE channel of the motherboard's onboard IDE controller. You should leave this enabled if you are using this onboard IDE channel. Disabling it will prevent the IDE devices attached to this channel from functioning at all.

If you are not attaching any IDE devices to this port (or if you are using a SCSI / external IDE card instead), you can disable this IDE channel to free an IRQ for other use.

Options : Enabled, Disabled

This option enables you to activate/inactivate the second IDE channel of the motherboard's onboard IDE controller. You should leave this enabled if you are using this onboard IDE channel. Disabling it will prevent the IDE devices attached to this channel from functioning at all.

If you are not attaching any IDE devices to this port (or if you are using a SCSI / external IDE card instead), you can disable this IDE channel to free an IRQ for other use.

Master/Slave Drive PIO Mode

Options : 0, 1, 2, 3, 4, Auto

This feature is usually found under the Onboard IDE-1 Controller or Onboard IDE-2 Controller option. It's linked to one of the IDE channels so if you disable one, the corresponding Master/Slave Drive PIO Mode option for that IDE channel either disappears or is grayed out.

This feature allows you to set the PIO (Programmed Input/Output) mode for the two IDE devices (Master and Slave drives) attached to that particular IDE channel. Normally, you should leave it as Auto and let the BIOS auto-detect the IDE drive's PIO mode. You should only set it manually for the following reasons :-

• if the BIOS cannot detect the correct PIO mode
• if you want to try to run the IDE device with a higher PIO mode than it was designed for
• if you have overclocked the PCI bus and one or more of your IDE devices cannot function properly (you can correct the problem by using a slower PIO mode)

Note that overclocking the PIO transfer rate can cause loss of data.

Below is a table of the different PIO transfer rates and their corresponding maximum throughputs.

Master/Slave Drive UltraDMA

Options : Auto, Disabled

This feature is usually found under the Onboard IDE-1 Controller or Onboard IDE-2 Controller option. It's linked to one of the IDE channels so if you disable one, the corresponding Master/Slave Drive Ultra DMA option for that IDE channel either disappears or is greyed out.

This feature allows you to enable or disable UltraDMA support (if available) for the two IDE devices (Master and Slave drives) attached to that particular IDE channel. Normally, you should leave it as Auto and let the BIOS auto-detect if the drive supports UltraDMA. If it does, the proper UltraDMA transfer mode will be enabled for that drive, allowing it to burst data at up to 100MB/s. You should only disable it for troubleshooting purposes.

Note that setting this to Auto does not enable UltraDMA or any of the slower DMA mode for IDE devices that do not support UltraDMA. Also, in order for any of those DMA modes to work (including the UltraDMA modes), you will have to enable DMA transfer via the OS. In Win9x, that can be done by ticking the DMA checkbox in the properties sheet of that IDE drive.

Below is a table of the different DMA transfer rates and their corresponding maximum throughputs.

Ultra DMA-66/100 IDE Controller

Options : Enabled, Disabled

This option allows you to enable or disable the extra onboard UltraDMA 66/100 controller (if available). This does not include the built-in IDE controller of the Intel ICH1 and ICH2 or VIA chipsets which already support UltraDMA 66/100. This function is only for the extra IDE controller (from HighPoint or Promise) that has been included onboard the motherboard, in addition to the built-in IDE controller of the chipset.

If you have one or more IDE devices attached to this UltraDMA 66/100 controller, you should enable this function in order to be able to use those IDE devices. You should only disable it for the following reasons :-

• if you don't have any IDE device attached to the additional UltraDMA 66/100 controller
• your motherboard doesn't have an extra UltraDMA 66/100 controller onboard
• for troubleshooting purposes

Note that disabling this function may cut down booting time. This is because the IDE controller's BIOS won't be loaded and thus there won't be a need to wait for it to query for IDE devices on its IDE channels. So, if you don't use it, it might be best to disable it.

USB Controller

Options : Enabled, Disabled

This function is similar to Assign IRQ For USB. It enables or disables IRQ allocation for the USB (Universal Serial Bus). Enable this if you are using a USB device. If you disable this while using a USB device, you may have problems running that device. However, if you don't use any USB devices, set the option to Disabled. It will free up an IRQ for other devices to use.