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Safe BIOS Setup Procedure

This procedure describes how to set the most important BIOS parameters to "safe" settings. The focus here is on maximizing the likelihood of the system functioning properly. You will want to use this procedure when setting up a new system or when having problems with the PC. Setting the BIOS to low-risk values can help greatly to expose problems with a system and help you eliminate them. Note that I do not describe all of the various BIOS settings here; see this Reference Guide section for details on BIOS settings. This procedure is based on the structure in that section.

Procedure Overview:

  • Difficulty Level: 3 (Moderate). BIOS settings can be somewhat confusing if you are new to them.
  • Risk Factor: 1 (Very low).
  • Hardware Required: None.
  • Software Required: None.
  • Time to Perform: 5 to 10 minutes.
  • Preparation / Warnings:
    • You should enter the BIOS setup program before starting this procedure, obviously.
    • If this is a system that has been set up previously, you may want to consider loading the default BIOS settings before commencing. I strongly advise you to back up the current BIOS settings before you do this.
    • For assistance working within the BIOS setup program, reference this section.
    • BIOSes vary widely. Make sure to check your particular BIOS setup program and make whatever modifications are necessary to this procedure to suit your system.
    • I do not cover all possible BIOS settings here, only the most important ones for proper system operation.
    • This procedure is geared towards modern Pentium-class or later systems. Older PCs will vary significantly.
    • Be sure to remember to save your changes before quitting, or you will end up doing this all over again.

Procedure Steps:

  1. Autodetect Hard Disk: Find the entry in the BIOS setup menu for autodetecting your hard disk and use it. This should detect your hard disk and set up its basic parameters. Note that some systems do not have a separate entry in the menu for autodetecting hard disks, but instead have autodetection as an option in the Standard Settings menu, where the hard disk parameters themselves are. See this section for more information on autodetection.
  2. Set Standard Settings: Enter the Standard Settings menu and configure the following options:
    • Date: Make sure you enter this in the correct format, usually MM/DD/YY.
    • Time: This is normally entered in 24-hour clock format.
    • IDE Primary Master / Primary Slave / Secondary Master / Secondary Slave: These entries contain the parameters for your IDE/ATA devices. If you successfully autodetected your hard disk(s) in the previous step then you should see the hard disk parameters that the BIOS found displayed here. These parameters are discussed in detail in this section. If your system does not have a separate autodetection menu item, it probably autodetects devices by pressing {Enter} while the cursor is on the "Type" setting; look at your motherboard or system manual. You'll have to autodetect each drive individually. I would recommend that you verify that the autodetection set the hard disk settings correctly by going through this list, because sometimes the settings are either not correct, or the BIOS tries to pick the most optimal values (and we are looking for safe values here):
      • Type: This should normally be set to "User" for hard disks. If your system has it, set this to "CD-ROM" for your CD-ROM drive.
      • Size: This is calculated and not something you can enter. Don't worry about it.
      • Cylinders / Heads / Sectors / Write Precompensation / Landing Zone: These should be left at the values that were autodetected.
      • Translation Mode: For most modern hard disks, this should be set to "LBA". Older hard disks below 504 binary megabytes (528 decimal megabytes) should be set to "Normal" or "CHS", depending on the BIOS. Do not change the translation mode on a drive that already contains data or you may trash the drive's contents.
      • Block Mode: This is supported by most hard disks but should be disabled for maximum compatibility.
      • PIO Mode: This can normally be left at whatever the BIOS detected. However, if the BIOS set it to a value that you know exceeds the maximum for the drive, reset it to whatever the maximum is. You may want to try lowering this value if you experience problems with your system. CD-ROMs generally have a maximum PIO mode of 3.
      • 32-Bit Transfer Mode: Disable this for maximum compatibility; you can re-enable it later.
    • Floppy Drive A / Floppy Drive B: Set these to the correct type for the floppy drive(s) in your system.
    • Video Display Type: Set to "VGA" or "VGA/EGA".
    • Halt On: Set to "All Errors" to make sure that all errors are trapped by the BIOS.
  3. Set Advanced Features: Enter the Advanced Features menu and configure the following options:
    • Virus Protection / Virus Warning: I would strongly recommend disabling this while configuring or setting up a system, or it will drive you nuts interrupting you with warning messages when you partition and format your hard disk.
    • Internal Cache: This should be enabled. If you have to disable this to get the system to work then you have a motherboard or CPU problem that will undoubtedly manifest itself in other ways (as well as seriously degrading performance).
    • External Cache: This too, should be enabled at all times. If disabling this is required for stable operation, you probably have a motherboard hardware problem. It may also be a CPU problem, especially with processors that have integrated level 2 cache.
    • Quick Power On Self Test / Quick Boot: Disable this to ensure that all POST tests are performed at boot time.
    • Boot Sequence: The options for this parameter depend entirely on the system. You want to choose a sequence that has the floppy disk (A:) first, so that your boot disk will work properly.
    • Swap Floppy Drives: Make sure this is set correctly (normally you want it disabled) or you are going to be mighty confused about the behavior of your floppy disk drives.
    • Fast A20 / A20 Gate Option: Disable this for maximum compatibility.
    • Video BIOS Shadow: Disable for maximum compatibility.
    • System BIOS Shadow: Disable for maximum compatibility.
    • xx00-xxFF Shadow: There will be a number of options for shadowing various ranges of upper memory. Ensure that all of these are disabled.
  4. Set Advanced Chipset Features: Enter the Advanced Chipset Features menu and configure the following options. Bear in mind that for the mostpart you will not want to move these values from their defaults:
    • Chipset Special Features / Global Features: Disable this for now.
    • Cache Timing: Leave this on "Auto" or whatever the appropriate setting is for your type of cache.
    • Level 2 Cache Size: If your system has this option, set it appropriately.
    • DRAM Parity Checking: Enable this if using parity or ECC memory.
    • DRAM Parity / ECC Mode: Leave this on "Parity" if using true parity memory. Set to "ECC" if using ECC memory. Parity mode is preferred for a new system or while debugging as it will tell you immediately if a problem situation is arising.
    • DRAM Speed / DRAM Timing / DRAM Auto Configuration: Set this to either "Auto" or to the correct speed of the memory you have installed. This should lock out most of the other options in this section.
    • DRAM Speculative Leadoff: If this option is not locked out, disable it.
    • Turn-Around Insertion: If this option is not locked out, disable it.
  5. Set PCI / PnP Configuration Settings: Enter the PCI / PnP Configuration menu and configure the following options. Bear in mind that for the mostpart you will not want to move these values from their defaults; use "Auto" settings wherever possible:
    • Plug and Play Aware OS: If setting up a Windows 95 system, enable this, otherwise leave it disabled.
    • Automatic Resource Allocation: Leave this set to "Auto". This should lock most of the other settings in this section.
    • PCI VGA Palette Snoop: Disable unless you know for sure that your system requires it.
  6. Disable Power Management: Enter the Power Management menu. You should find that the first setting is some sort of global or master setting that controls all the other power management settings. I recommend that you disable this at first when setting up a new system, or if you are experiencing hardware or system problems. Note however that if you totally disable power management, this will also eliminate some advanced power features such as the ability to have Windows turn off the PC on an ATX form factor system. As an alternative, leave power management enabled but disable the standby/suspend timing parameters so that the BIOS does not automatically turn off parts of the system after a period of time.
  7. Set Integrated Peripherals Settings: Enter the Integrated Peripherals menu and configure the following options:
    • Integrated Floppy Disk Controller: Make sure this is enabled or your floppy disk will not function.
    • Integrated IDE / Hard Disk Controllers: You will either find two of these parameters--one for the primary IDE channel and the other for the secondary--or a single setting that controls both using options like "Disabled", "Primary", "Secondary" and "Both". Enable whichever channels you are using. Most systems will have at least one device on the primary channel. Some will also have a device on the secondary channel.
    • Integrated Serial Port 1 (COM1): You will normally want this enabled, and the standard resource setting is IRQ #4, with I/O address 3F8h.
    • Integrated Serial Port 2 (COM2): You will usually want this enabled, and the standard resource setting is IRQ #3, with I/O address 2F8h. Disable COM2 if you don't need it, or if you have or plan to install a modem configured using COM2's default resources. (Many modems come configured to use COM2 by default).
    • Integrated Parallel Port: You will normally want to enable this. The standard resource assignment is IRQ #7, with I/O address 378h (3BCh on some systems).
    • Integrated Parallel Port Mode: Set this to either "SPP" or "EPP". Do not set it to "ECP", as this mode involves the use of additional DMA resources and is less compatible.
    • PS/2 Mouse Enable: Set to "Auto" if your system has that option, otherwise enable it if using a PS/2 style mouse, disable otherwise.
    • USB Enable: Disable on most systems, unless using USB.
  8. Set Hardware Device Settings (jumperless systems only): If you have a jumperless motherboard, enter the "CPU Soft Menu" (or whatever it is called on your system) and configure your motherboard options:
    • CPU Operating Speed: If this option is present, set your CPU's speed here. This will set and lock the "External Clock" and "Multiplier Factor" settings.
    • External Clock: Set to the correct system bus speed for your PC.
    • Multiplier Factor: Set to the multiplier factor for your PC.
    • CPU Power Plane: Set to either "Single Voltage" or "Dual Voltage" depending on what your CPU requires.
    • I/O Plane Voltage: Set the appropriate external or I/O voltage for your processor.
    • Core Plane Voltage: Set the appropriate internal or core voltage for your processor.
  9. Save and Exit Setup: Return to the main menu and choose the option to save and exit the BIOS setup program. This will reboot the system. If you are setting up a new system, make sure your floppy boot disk is still in the floppy drive so that the system will boot from it.

Next: Post-Assembly Initial Test Procedure


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