BIOS Features Setup

Options : Normal, Fast

This feature determines how Gate A20 is used to address memory above 1MB. When this option is set to Fast, the motherboard chipset controls the operation of Gate A20. But when set to Normal, a pin in the keyboard controller controls Gate A20. Setting Gate A20 to Fast improves memory access speed and thus, overall system speed, especially with OS/2 and Windows.

This is because OS/2 and Windows enter and leave protected mode via the BIOS a lot so Gate A20 needs to switch often from enabled to disabled and back again. Setting this feature to Fast improves memory access performance above 1MB because the chipset is much faster in switching Gate A20 than the keyboard controller. It is recommended that you set it to Fast for faster memory accesses.

IDE HDD Block Mode

Options : Enabled, Disabled

The IDE HDD Block Mode feature speeds up hard disk access by transferring data from multiple sectors at once instead of using the old single sector transfer mode. When you enable it, the BIOS will automatically detect if your hard disk supports block transfers and configure the proper block transfer settings for it. Up to 64KB of data can be transferred per interrupt with IDE HDD Block Mode enabled. Since virtually all hard disks now support block transfers, there is normally no reason why IDE HDD Block Mode should not be enabled.

However, if you are running WinNT, beware. According to Chris Bope, Windows NT does not support IDE HDD Block Mode and enabling IDE HDD Block Mode can cause corrupted data. Ryu Connor confirmed this by sending me a link to a Microsoft article about Enhanced IDE operation under WinNT 4.0. According to this article, IDE HDD Block Mode (and 32-bit Disk Access) had been observed to cause data corruption in some cases. Microsoft recommends that WinNT 4.0 users disable IDE HDD Block Mode.

On the other hand, Lord Mike asked someone in the know and he was told that the data corruption issue was taken very seriously at Microsoft and that it had been corrected through Service Pack 2. Although he couldn't get an official statement from Microsoft, it's probably safe enough to enable IDE HDD Block Mode if you are running WinNT, just as long as you upgrade to Service Pack 2.

If you disable IDE HDD Block Mode, only 512 bytes of data can transferred per interrupt. Needless to say, that degrades performance quite a bit. So, only disable IDE HDD Block Mode if you are running WinNT. Other than that, you should enable it for optimal performance.

For more detailed information on IDE HDD Block Mode, check out our Speed Demonz' guide on IDE Block Mode!

32-bit Disk Access

Options : Enabled, Disabled

32-bit Disk Access is a misnomer because it doesn't really allow 32-bit access to the hard disk. What it actually does is set the IDE controller to combine two 16-bit reads from the hard disk into a single 32-bit double word transfer to the processor. This makes more efficient use of the PCI bus as fewer transactions are needed for the transfer of a particular amount of data.

However, according to a Microsoft article about Enhanced IDE operation under WinNT 4.0, 32-bit disk access can cause data corruption under WinNT in some cases. Microsoft recommends that WinNT 4.0 users disable 32-bit Disk Access.

If disabled, data transfers from the IDE controller to the processor will then occur only in 16-bits. This degrades performance, of course, so you should enable it if possible. Disable it only if you face the possibility of data corruption.

You can also find more information on the WinNT issue above in our Speed Demonz' guide on IDE Block Mode!

Typematic Rate Setting

Options : Enabled, Disabled

This feature enables you to control the keystroke repeat rate when you depress a key continuously. When enabled, you can manually adjust the settings using the two typematic controls (Typematic Rate and Typematic Rate Delay). If disabled, the BIOS will use the default setting.

Typematic Rate (Chars/Sec)

Options : 6, 8, 10, 12, 15, 20, 24, 30

This is the rate at which the keyboard will repeat the keystroke if you press it continuously. This setting will only work if Typematic Rate Setting is Enabled.

Typematic Rate Delay (Msec)

Options : 250, 500, 750, 1000

This is the delay, in milliseconds, before the keyboard automatically repeats the keystroke that you have pressed continuously. This setting will only work if Typematic Rate Setting is Enabled.

Security Setup

Options : System, Setup

This option will only work once you have created a password through PASSWORD SETTING out in the main BIOS screen.

Setting this option to System will set the BIOS to ask for the password each time the system boots up.

If you choose Setup, then the password is only required for access into the BIOS setup menus. This option is useful for system adminstrators or computer resellers who just want to keep novice users from messing around with the BIOS. :)