Motherboard BIOS Setting

Optimizing a PC's BIOS

Advanced settings for the fastest, most reliable white-box systems anywhere

byCarey Holzman on May 10, 2004, 12:45 pm EDT
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Last week, in part 1 of this two-part Recipe, I discussed what a BIOS is and why you need to configure it correctly to achieve both the fastest and most reliable scenario for your customers' computers. If you have not yet read Part 1, it is imperative that you do so before continuing. Part 1 can be found here.

This week, I will discuss advanced features of the BIOS. These include proper configuration of built-in peripherals, as well as power-management issues to consider. Let's dig in.

Advanced: Integrated Peripherals

This section of the BIOS contains settings for built-in peripherals included with the motherboard. This includes serial and parallel ports, as well as audio, LAN, and USB ports. Unused ports are a significant drain on resources and should be disabled.

Primary VGA BIOS: This setting is used only when there are two video cards installed in the PC: One AGP (accelerated graphics port) and one PCI (peripheral component interconnect). The system wants to know which card to initialize first and make its "main" card. If you only have one video card, it is most likely AGP. For most people, the default setting is wrong and should be changed to AGP VGA Card. If you have two video cards, select the video card that you want to be the "main" or primary card. The primary video card will show the Windows splash screen and POST results during initial boot-up.

USB Controllers: This feature allows you to limit your AGP functionality. You may choose to allow only AGP 1.1, AGP 1.1 and 2.0, or disable AGP altogether. Most people will want to set this to AGP 1.1 and 2.0 for maximum versatility.

USB Legacy Support: This setting must be enabled if the PC has a USB keyboard and the user wants to use this keyboard either in a DOS environment or before the operating system loads (boot menus, for example). If this setting is disabled, then booting to a floppy disk or CD-ROM will render the keyboard useless. Also, ironically, trying to enter the PC's BIOS may be impossible if this setting is disabled and a USB keyboard is involved. If the PC has a USB keyboard with a rectangular connector, then set this to Enabled. If it has a PS/2 keyboard (round connector), set this to Disabled. Be aware that enabling this feature may result in problems with the computer waking up from Standby or Hibernate mode, or the computer may not shut down properly. In other words, enable this only if you must.

USB Mouse Support: Same as above. Disabled is the preferred setting.

Onboard AC97 Audio Controller: If a sound card such as a Soundblaster Audigy has been added to the PC, or the system does not have speakers, be sure to Disable the motherboard's on-board sound card. This will free up precious resources and prevent potential conflicts. For most systems, however, this feature should be set to Enabled.

Onboard AC97 Modem Controller: Some motherboards are sold with built-in or proprietary dial-up modems. This is rare on white-box systems, but many tier-one manufacturers utilize these devices. If the system lacks a modem, or if the modem is plugged into a standard PCI slot on the motherboard, then this setting should be Disabled. Otherwise, it should be Enabled.

Onboard LAN (nVidia): This lets you enable or disable the built-in network interface card (NIC). The options are Auto or Disabled. The ASUS motherboard I used for this Recipe has two built-in network interface cards. This is particularly useful for people who want to use the PC as a router to share their high-speed broadband Internet connection. One NIC plugs into the cable modem, while the other NIC plugs into a hub, switch, or other PC via a crossover cable. If your customer, like most people, uses only one NIC, disable the one they are not using to free up valuable resources. Note: Both NICs are created equal, and there is no benefit to using one over the other.

Onboard LAN (3Com): This is the second built-in network interface card (NIC), as mentioned above. If the customer doesn't use both NICs, disable the one they are not using to free up system resources.

Onboard 1394 Device (Firewire): This feature enables or disables the built-in IEEE 1394 (also known as Firewire) port on the PC. If the system does not have any Firewire devices, or if the Firewire connector is not plugged into the motherboard (some motherboard manufacturers sell them separately), disable this device to free up valuable resources.

Floppy Disk Access Controller: Most PCs today do not have floppy drives. If that's the case for your customer's PC, or if they never use their floppy drive and would rather have resources available for other things, then disable this device. Note: If your customer has a floppy drive and decides to disable it here, the drive will not function unless you go back in to the BIOS and re-enable it.

Onboard Serial Port 1: Most people no longer use serial ports for connecting external peripherals, as most serial devices have been replaced by USB equivalents. If your customer does not use the system's serial ports, disable the ports and free up the resources for other things. On the other hand, if your customer does use the serial port, then this setting should be set to 3F8/IRQ4.

Onboard Serial Port 2: Same as above if your customer does not use this. If they do use it, then set this to 2F8/IRQ3.

UART2 Use As: A UART (Universal Asynchronous Receiver/Transmitter) is a chip that receives and transmits data serially; each serial port you have will use one, though it is possible that several may be integrated onto one chip. Many motherboards offer an infrared device to use in place of Serial Port 2. This is where you can make that decision. You will need the infrared adapter installed on your specific motherboard, usually sold separately, to utilize the Infrared feature.

Onboard Parallel Port: This setting lets you decide whether to select parallel port mode resources or disable the parallel port completely. If your customer has nothing plugged into the parallel port, disabling it will free up valuable system resources. But if they use the parallel port, then I recommend you set it to: 378/IRQ7.

Parallel Port Mode: If you have disabled the parallel port, then this setting is irrelevant. However, if the parallel port is enabled, you should configure it to run in EPP (enhanced parallel port) or ECP (enhanced capabilities port) mode. EPP mode is recommended if the system has just one device, such as a printer, plugged into its parallel port. Select ECP if you have daisy-chained more than one device -- such as an external Zip drive, scanner, printer, or tape drive -- to the system's parallel port. To take full advantage of these settings, make sure you're using IEEE-1284-compliant parallel cables.

ECP DMA Select: If you select ECP or EPP plus ECP as your parallel port mode above, then this option is made available to you. With it, you can select which DMA (Direct Memory Access) channel you want it to use. I recommend the default setting of 3.

Onboard Game Port: If your customer has added a sound card to the system, or if they do not use either MIDI-devices or obsolete joysticks, then this feature should be disabled to free up resources. If, however, they do use the onboard game port, then I recommend the default setting of 201.

Onboard MIDI I/O: MIDI (Musical Instrument Digital Interface) defines the standard that lets musical instruments, computer hardware, and software communicate. If your customer doesn't use their computer for making or playing MIDI music, you can safely disable this device. Otherwise, I recommend the default setting of 330.

Onboard MIDI IRQ: Same as above. If enabled, I recommend the default setting of 10.

Advanced - Power Management Setup

This area of the BIOS seems to be the most misunderstood. It is primarily responsible for systems that do not shut down correctly or that enter or awaken from the Standby or Hibernate mode when these settings are not properly configured. Since Windows has built-in power management, you'll want to disable all power management in the BIOS. Otherwise, the two fight with each other, and neither works properly. Motherboard manufacturers don't assume everyone is using Windows, and many of these settings exist for non-Windows users.

ACPI Suspend to RAM: ACPI stands for Advanced Configuration and Power Interface, not to be confused with APIC or IPCA, which some people may find as an option in their BIOS. The Suspend to RAM feature, sometimes referred to as S3/STR, lets the PC save more power when in Standby mode. But all devices within or attached to the computer must be ACPI-compliant. Some BIOS's offer an S1/POS option for this scenario. If you enable this feature and experience problems with the standby mode, simply go back into the BIOS and disable it.

Video Off Method: The DPMS (Display Power Management System) option allows the BIOS to control the video display card if it supports the DPMS feature. The Blank Screen option simply blanks the screen -- use this for monitors without either power-management or "green" features. The V/H SYNC Blank option blanks the screen and turns off the vertical and horizontal scanning. If the computer and monitor were built within the last four years, I recommend setting this to DPMS.

HDD Down In Suspend: This feature determines whether the hard-disk drive is automatically shut down when the computer enters Suspend mode. While most power settings of this type are controlled within Windows, if you find the hard drive is not powering down when the computer enters Suspend mode (assuming your customer even uses suspend/hibernate mode), then enable this option. Otherwise, the recommended setting is Disabled.

PWR Button : By default, all ATX computers will power off after the power button is held for more than four seconds. This setting tells the computer what to do if the power button is held down for less than four seconds. The options are: power off or enter suspend mode. This setting is up to you.

Power Up On PCI Device: If your customer uses Wake-On-LAN (typically used in large office environments to turn on computers remotely for remote administration), you will want this setting Enabled. Otherwise, I recommend you set this to Disabled.

Wake/Power Up on Ext. Modem: This setting tells the computer to turn itself on when a phone line plugged into its modem rings. Once again, this is used for remote administration. For other settings -- in other words, most users -- I recommend you set this to Disabled.

Automatic Power Up: This feature, if enabled, lets you designate a specific time each day when the PC will turn itself on. If that's useful to the customer, set it to Enabled. Otherwise, I recommend Disabled.

Time (hh:mm:ss) of Alarm: This field sets the time for automatic power-up, based on a military/24-hour clock. The Automatic Power Up field must be enabled to use this feature.

AC Power Loss Restart: This option lets you tell the PC what to do in the event of a power loss. Disabled leaves the system off. Enabled reboots the system. Previous State sets the system back to the state it was in before the power interruption. I recommend you set this to Disabled.

Power On By PS/2 Mouse: When enabled, this feature allows the use of a PS/2 (not USB) mouse to turn on the system. Disabled is recommended so your customer doesn't accidentally keep turning on their computer.

Power On By PS/2 Keyboard: When enabled, this feature lets specific keys on a PS/2 keyboard be used to turn on the system. Disabled is recommended, as most people find this more of an annoyance when they accidentally press a wrong key.

Advanced - PnP/PCI Configurations

This area of the BIOS exists primarily for compatibility with old or unusual hardware. Most people will not need to make any changes from the factory default settings.

Reset Configuration Data: The Extended System Configuration Data (ESCD) contains information about non-PnP (plug and play) devices only. It also remembers the configuration of the system since the last time it was booted. Enable this feature if you want the system to clear this data during the Power-On-Self-Test (POST). This is typically used when diagnosing a piece of hardware that is not working correctly. Once you've Enabled this and exited the BIOS, the data will be cleared, and the setting will automatically be returned to Disabled.

Resources Controlled By: This setting tells the computer to either set IRQs automatically or to allow for all devices to be assigned IRQs manually. Manual IRQ selection can be quite challenging and is usually only required when working with older, non-PnP compliant peripherals. The recommended setting is: AUTO(ESCD).

IRQ Resouces: This option allows for manual IRQ configuration and will only be available as an option if you selected MANUAL in the previous setting.

PCI/VGA Palette Snoop: This feature is typically used by video add-on cards, such as MPEG encoders. They do not have their own palette, so they must borrow or "snoop" the palette from the system's video card. If, like most people, your customer does not have a secondary video device plugged into the video card, then this setting should be set to Disabled.

Security Menu
The security section of the BIOS is used to keep unauthorized people from making any changes to the BIOS. Because settings in the BIOS are so critical to proper PC operation, many office IT staff choose to lock out all non-IT personnel by using a password that only IT personnel have access to.

Security Option: This feature lets you password-protect the BIOS to prevent unauthorized users from making changes. It can also be set to require a password at boot-up. The options available are Setup or System and define the limitations of the options below.

Set Supervisor Password: If you choose to select a Supervisor Password, a password will be required to enter the BIOS after you chose SETUP, as described above. If you choose SYSTEM as described above, then a password will be required for booting, too.

Set User Password: A different password assigned to users is required to boot the PC and permits the user to only adjust the date and time in the BIOS if a Supervisor Password has also been selected.

Note: If these passwords are forgotten or lost, you will have to reset the BIOS back to factory defaults by temporarily moving a jumper on the motherboard.

Hardware Monitor Menu

This part of the BIOS displays and sometimes monitors voltages, fan speeds, and temperatures. The ASUS motherboard used in this Recipe even lets you set the system to automatically slow or speed its fans depending on the system's internal temperature. You may also be able set a CPU warning temperature that will sound an alarm. Some BIOS's, even have the option of powering down the system once a pre-set temperature has been exceeded, or if the fan is turning too slowly or not at all. This can prevent the CPU from burning up.

If the BIOS has these options, you will find them all here, and they should be labeled clearly. Because today's CPUs run extremely hot, enabling features that monitor and prevent permanent damage to the entire system is just common sense. I recommend you take advantage of them.

Each CPU has individual heat limitations. An example of AMD Athlon CPUs heat thresholds can be found in a table located in part 1 of this recipe (scroll down to find it). Generally speaking, if the option to issue an warning beep or shut down the computer if a specific temperature is reached or exceeded exists in the BIOS, there will be several pre-set temperatures to choose from. I recommend setting it to the second hottest temperature option offered.

Exit Menu
This is where you can discard all the changes you've made, save them, or reset every BIOS setting back to its factory default.

Because there are so many potential different options available in a computer's BIOS, you may have features and options not covered here. For additional information and answers to many BIOS questions, I recommend these two Web-sites: Wim's BIOS and Adrian's RojakPot.

Good luck with your BIOS optimization.