By modifying settings in your BIOS you can improve performance, reduce boot time, fix incompatibility problems & many other things. This guide will take you through the BIOS & how to update it, change setting to improve performance, etc. & how to overclock your system using BIOS settings too.

BIOS flashing

You should begin by updating your BIOS to the latest version. This can fix issues with certain motherboards, add more features or just improve performance. Although BIOS flashing is a little more dangerous than say, updating drivers as if you do it wrong you may need a new motherboard or BIOS chip. As a result I'd recommend that if you're happy with your PC as it is then you can probably skip this section. Given the potential risks involved with this its highly recommended you backup important data. You can find a list of motherboard manufacturers (& their BIOS updates) at Windrivers.

Your manufacturers website may also contain instructions on how to flash your BIOS. NOTE - BIOS flashing can only be completed in DOS mode & not in Windows9x/NT.

What to do

·         Begin by downloading the BIOS update & a BIOS flashing utility, e.g. Award Flash utility.

·         Make a bootable floppy disk (startup disk), Windows 2000 (& other) users can download one here. A standard Windows 98 bootdisk will suffice.

·         Extract the files from the BIOS update & the BIOS Flashing utility & copy them onto the floppy disk (BIOS update will end with the .bin, binary file extension).

·         Restart your system & boot from the floppy drive (you may need to make changes in your BIOS to do this, its also recommended that you Load BIOS defaults before doing so).

·         Ensure that no memory managers are running by typing in MEM /c or MEM /d at the command prompt. If they are you may need to edit the config.sys file on the disk to remove the references to them (EMM386.EXE & HIMEM.SYS). You'll need to load up Windows to do this. Open A:\config.sys with Notepad & delete those lines. Reboot then using the bootdisk.

·         Type A:\ to go into the floppy drive where you can being the Flashing process.

·         Update the BIOS via the Flash utility, e.g. To use the Award Flash utility you should enter in AWDFLASH.EXE. Substitute in the appropriate filename if necessary.

·         You will be asked for the file name to program, enter in the name of the *.bin file on the disk, e.g. NEW.BIN. Hit Enter to continue.

·         You may be prompted to save your current BIOS. Do so at your own discretion, e.g. Save it as BACKUP.BIN.

·         The BIOS update procedure will now begin. Do NOT interupt this procedure in any way. You will be told what to do & when to do it.

BIOS settings

You can boot up faster & improve your performance by changing settings in your BIOS. First of all need to access it. When you're starting the PC, hit the Delete key. It should bring up the BIOS a few seconds later. Use another key if necessary.

NOTE - Write down all your current settings for future reference in case you do something that you shouldn't have. Either that or want you just want to restore it to your old configuration. Some of the definitions used are taken from my VT6X4 manual.

You may need to search under different sections of your BIOS to find these, so be prepared to look. I'll put these into different sub-categories where they generally would appear.

Standard CMOS features

Date: Use this to set the date for the computer to use.

Time: Use this to set the time for the computer to use.

IDE Primary master: There are more options available for selection in a submenu. Many of the parameters for the options below will be shown on your hard drive, so write them down if possible (Note these fields are only necessary for hard drives, not for DVD drives, etc.). Many of the settings used here will be printed on your hard drive.

·         IDE HDD auto-detection: This can be used to auto-detect all parameters for the values shown below. Press Enter to try auto-detection.

·         Access mode: Use this to set the access mode for the hard drive. Set this to Auto if you are unsure. Set to Normal if the hard drive is less then or equal to 528MB (highly unlikely now). Set to LBA (Logical Block Addressing) for large disk support. If LBA mode is not supported try Large mode instead.

·         Capacity: Enter in the size (in MB) of the hard drive.

·         Cyclinder: Use this field to set the number of cyclinders on the hard drive.

·         Head: Use this to set the number of read/write heads on the hard drive.

IDE Primary slave: See IDE Primary master.

IDE Secondary master: See IDE Primary master.

IDE Secondary slave: See IDE Primary master.

Drive A: Select the type of floppy drive you have installed in your machine, if any.

Drive B: Select the type of the second floppy drive you have installed in your machine, if any.

Floppy 3 mode support: If you are using a Japanese PC then you'll most likely be using this type of floppy drive, in which case you should set it to Drive A/B depending on which drive it is installed as. All others should set this to Disabled.

Advanced BIOS features

Virus warning: When Enabled if any attempt to access the Boot sector or Partition table is made the BIOS will warn you & either ask you too allow it to make changes or disable any changes. While safer to leave enabled it can interfere with certain updates & programs, particularly Partition Magic. I'd recommend leaving it set to disabled.

CPU L1: Make sure to enable this if not already enabled. The L1 cache is effectively extremely fast RAM, running at the same speed as the processor.

CPU L2 cache: Make sure to enable this if not already enabled. Some PC's (e.g. K6-3) may contain a L3 cache. Although most won't, but enable it if it does. The L2 cache is effectively extremely fast RAM, although the L2 cache generally runs at a fraction of CPU speed. On Pentium 3 E, or EB models the L2 cache runs at the same speed as the processor.

CPU L2 cache ECC checking: set this to enabled. It will check your L2 cache for errors & can fix some of them. This will improve to the stability of your PC.

Quick power on self test: When booting up a series of tests are run on a system. Enabling this feature will simplify these tests resulting in a faster boot-up. You should Disable this if your system is experiencing problems.

Boot order: For fastest boot up select your hard-drive only, usually C:. If you encounter problems you can change this later on.

First boot device: Selects the first bootable device, choose where your operating system is stored, usually HDD-0 (Choose SCSI if appropriate). If you need to boot from a Floppy disk or CD-ROM, select appropriately. If this fails it will check the second boot device for a bootable media. NOTE - For optimal boot time set this to wherever your OS is stored.

Second boot device: Selects the second bootable device, where your operating system is stored, usualy HDD-0. If this fails it will check the third boot device for a bootable media. NOTE - For optimal boot time set this to Disabled.

Third boot device: Selects the third bootable device. If this fails it will check the other boot device for a bootable media. NOTE - For optimal boot time set this to Disabled.

Boot other device: Selects the other bootable device. NOTE - For optimal boot time set this to Disabled.

Swap Floppy drive: This allows for quick swapping off floppy drive names, i.e. your A: drive changes to B: & B: changes to A:. By default this is Disabled & should be left at this unless you have, 1. - Multiple floppy drives (unlikely) & Need to swap around their drive names without having to swap cables around.

Boot up floppy seek: Use this setting to determine whether or not the BIOS will try to detect a FDD (Floppy Disk Drive) in your system. If enabled & no FDD is present then an error message will be displayed. I'd recommend setting this to disabled to skip this test & improve boot time.

Boot from floppy: disable this, if something happens you can re-enable it, but for now it slows boot-time. Only needed when you want to load from a bootable floppy, e.g. When wanting to flash your BIOS.

Advanced BIOS features (Cont.)

Typematic Rate setting: This allows to edit the 2 settings below. Enable or Disable as you see appropriate.

Typematic Rate (Chars/sec): This is the frequency at which the keyboard will repeat a keystroke, e.g. If set to 6 then the key will repeat the same character 6 times per second. This setting is the same as the Repeat rate in Keyboard properties applet in the Control panel.

Typematic Rate Delay (msec): This sets the delay in milli-seconds that you can hold a key down before it gets repeated, e.g. If set to 500msec, then you can hold down a key for 1/2 a second before it starts repeating. This setting is the same as Repeat delay in Keyboard properties applet in the Control panel.

Security option: Settings available for this are System or Setup. Depending on which option is selected a user will prompted to enter in a password when either - booting the system (System) or when trying to enter the BIOS (Setup). See later on in the guide for where to set the password.

OS select for DRAM > 64MB: If you have 64MB RAM or more in your system & are running OS/2 then set this to OS/2. If you have another operating system installed select Non-OS/2.

Report no FDD for Win95: If using Windows 95 (still) & have no Floppy drive in your machine set this to Yes, otherwise leave it at No.

Fast Gate A20 Option: A20 refers to the high memory area (First 64KB of extended memory). This option uses the fast gate A20 line (if supported) to access memory above 1 MB. This is faster than the normal method. Set it to enabled for better performance.

Video BIOS shadowing: Your system will perform better with this setting at disabled. As you can read in the MS Knowledge base, shadowing is not an advantage. Only enable this if you still use DOS mode a lot, where it can improve performance.

Video BIOS cacheable: set this to disabled. Your system does not access the video cards BIOS, it uses drivers to do so. Only enable this if you still use DOS mode games a lot, where it can improve performance.

Shadow xxxxx - xxxxx: Where, xxxxx - xxxxx represents the address ranges to be shadowed in RAM. I'd recommend setting these to Disabled. This can improve system stability.

Integrated peripherals

Onboard IDE-1 controller: Leave this set to Enabled. NOTE - DMA has vastly higher data transfer rates than PIO mode does.

·       Master drive PIO mode: Use this to set the PIO mode (0 - 4) data transfer rate for the master drive. The PIO mode data transfer rates are; Mode 0 - 3.3MB, Mode 1 - 5.2MB, Mode 2 - 8.3MB, Mode 3 - 11.1MB, Mode 4 - 16.6MB.

·       Slave drive PIO mode: Use this to set the PIO mode (0 - 4) data transfer rate for the slave drive. The PIO mode data transfer rates are; Mode 0 - 3.3MB, Mode 1 - 5.2MB, Mode 2 - 8.3MB, Mode 3 - 11.1MB, Mode 4 - 16.6MB.

·       Master drive Ultra DMA: If the master drive supports DMA then set this to Auto & the optimal DMA mode will be auto-detected for that drive. If only PIO transfer mode is supported set it to Disabled.

·       Slave drive Ultra DMA: If the slave drive supports DMA then set this to Auto & the optimal DMA mode will be auto-detected for that drive. If only PIO transfer mode is supported set it to Disabled.

Onboard IDE-2 controller: Leave this set to Enabled, unless you have no devices attached to your secondary IDE channel (highly unlikely). NOTE - DMA has vastly higher data transfer rates than PIO mode does.

·       Master drive PIO mode: Use this to set the PIO mode (0 - 4) data transfer rate for the master drive. The PIO mode data transfer rates are; Mode 0 - 3.3MB, Mode 1 - 5.2MB, Mode 2 - 8.3MB, Mode 3 - 11.1MB, Mode 4 - 16.6MB.

·       Slave drive PIO mode: Use this to set the PIO mode (0 - 4) data transfer rate for the slave drive. The PIO mode data transfer rates are; Mode 0 - 3.3MB, Mode 1 - 5.2MB, Mode 2 - 8.3MB, Mode 3 - 11.1MB, Mode 4 - 16.6MB.

·       Master drive Ultra DMA: If the master drive supports DMA then set this to Auto & the optimal DMA mode will be auto-detected for that drive. If only PIO transfer mode is supported set it to Disabled.

Integrated peripherals (Cont.)

IDE prefetch mode: If you IDE interface supports IDE prefetching this will allow for faster drive access. Enabled is faster, only disable if not supported.

Init display first: If you have only 1 graphics card in your system this can be ignored. If you have multiple graphics cards in your system, select either PCI or AGP depending on which one you want to use. This is useful for those of you who have motherboards with graphics cards soldered into the motherboard.

USB controller: If you use USB devices then you'll need to leave this enabled. Otherwise disable it, you'll free up an IRQ in the process too.

IDE HDD Block Mode: This setting allows for multi-sector transfers, enabled is faster.

IDE 32-bit transfer mode: Select enabled to use 32-bit I/O accesses with your hard drive. This is faster, although it has been known to cause data corruption in Windows NT.

Onboard FDD controller: If you use FDD's (Floppy Disk Drives) then you'll need to have this enabled.

Onboard serial port 1: Use this to set/disable/change the address for Serial port 1. You can manually select an address for it, e.g. 3E8/IRQ4, disable it altogether or set it to Auto. I'd recommend leaving it set to Auto.

Onboard serial port 2: Use this to set/disable/change the address for Serial port 2. You can manually select an address for it, e.g. 3E8/IRQ4, disable it altogether or set it to Auto. I'd recommend leaving it set to Auto.

Onboard parallel port: Sets the address for the parallel port to use. Leave it at the default setting unless you need to change it to fix a resource conflict.

Parallel port mode: Use this to select the operation mode for the Parallel Port. You may need to check your motherboard manual to find this out. ECP mode being the best. Depending on your choice one of the following submenus may become available.

·       ECP mode use DMA: Use this to select the DMA channel for ECP or ECP+EPP to use.

PNP/PCI configuration

Assign IRQ for USB: If you're not using any USB hardware then you can safely disable this & free up an IRQ. If you are using USB hardware then leave this enabled.

Assign IRQ for VGA: Set this to enabled. Nearly all video cards now need an IRQ assigned to them to function correctly.

PCI/VGA palette snoop: If you have an MPEG card or add-on card then you should try set this to enabled to remove the colour inversion that can occur. Disable it if you have no MPEG card in your machine, or do not get affected by any colour inversion.

PNP OS Installed: Set it to Yes to to allow your Plug & play compatible operating system, e.g. Windows 98, to manage resources. Setting it to No will let the BIOS handle this.

Resource Controlled By: Most users should let this be set at Auto. You should only set it to manual if you need to reconfigure your IRQ/DMA settings.

Advanced chipset features

AGP-4X mode: If your graphics card supports it then set this to enabled. With some older graphics cards you may need to disable AGP-4 in order for them to work.

AGP aperture size: If you have an AGP graphics card then you'll want to change the Aperture size. Check your graphics card manual to see if there is any guideline on setting the aperture size. If not try setting it at either half or a quarter of your system RAM. You may want to try other values however.

AGP driving control: This setting allows you to adjust the AGP driving force. It is recommended you leave this set to Auto.

AGP master 1 WS write: When enabled a single wait state is used when writing to the AGP bus. When disabled a 2 wait state is used. For optimal performance set this to enabled. For improved stability set it to disabled.

AGP master 1 WS read: When enabled a single wait state is used when reading to the AGP bus. When disabled a 2 wait state is used. For optimal performance set this to enabled. For improved stability set it to disabled.

Advanced chipset features (Cont.)

CPU to PCI write buffer: When enabled, the CPU can write up to 4 dwords of data to the PCI write buffer before the CPU must wait for the PCI bus cycles to finish. When disabled, the CPU must wait after each write cycle until the PCI bus signals that it is ready to receive more data. Set this to enabled to improve performance.

Delayed Transaction: This is required for compliance with the PC 2.1 specification. It allows for support of delay transaction cycles. Set it to enabled.

DRAM Clock: With the VIA Apollo 133 based motherboards you have the option to change SDRAM speed. Settings available are Host CLK or +/-33. Host CLK allows the SDRAM to run at the same speed as the Ext. Clock (FSB). You can use the +/-33 in case you want to run the RAM slower/faster than the Ext. Clock, e.g. If you Ext. Clock is 100Mhz you could use +33 to allow your SDRAM to run at 133Mhz. Which is a great option for those of you with PC 133 SDRAM. Or alternatively you could run at a 133Mhz Ext. Clock while your RAM runs at 100Mhz by using the -33 setting. Or you could run PC133 RAM at 133Mhz on a 133Mhz Ext. Clock (aka FSB) by using the Host CLK option. As you can see this option allows for a great deal of possibilities.

DRAM speculative leadoff: enable this for better performance, althought it could make your system less stable, disable it if it does.

DRAM Data Integrity Mode: In the unlikely event you have ECC (Error Correcting Code) memory installed then you should set this to ECC, otherwise set it to non-ECC. Most memory is non-ECC & not really recommended for most users unless the need the added stability (but it is slower when ECC is being used).

Delay DRAM read latch: The lower the value for this the better the performance, although stability may be affected. Higher values may improve system stability.

Fast writes: Setting this to Enabled should improve performance on graphics cards that supports it, e.g. GeForce cards. Although for most users it adversely affects performance. So I'd recommend you try both Enabled & Disabled to decide. Only try this if your graphics cards support Fast writes. If it doesn't leave it Disabled.

Memory Hole At 15M-16M: Some old add-in cards need this enabled to work properly. If you have such a card then enable this, otherwise disable it.

Memory parity/ECC check: This allows the BIOS to check memory is parity/ECC module or not. Setting this to disabled should improve performance. Enabled may improve stability at the cost of performance.

On-board/chip sound: If your motherboard has a built-in soundcard, such as the Abit VT6X4, you may choose to disable this if you want to use your own one instead. Disable it if so.

On-board/chip video: If your motherboard has a built-in videocard, you may choose to disable this if you want to use your own one instead. Disable it if so.

Passive Release: Passive release is intended to lower CPU utilisation by allowing bus mastering devices to access RAM interleaved with CPU accesses. Most useful when playing multimedia files (such as MPEG's or other streaming multimedia). You should enable this if you fall into that category, otherwise disable it.

Advanced chipset features (Cont.)

PCI master 0 WS write: When enabled no (zero) wait states are used when writing to the PCI bus. When disabled 1 wait state is used. For optimal performance set this to enabled. For improved stability set it to disabled.

RAS active time: a high number will increase performance of the system's SDRAM. Decrease this if stability is affected.

RAS to CAS delay: this should be set to a low number, althought it is affected by the quality of you RAM, so set it higher if you have any difficulties afterwards.

Read around write: This is a DRAM optimization feature. If a memory read is addressed to a location whose latest write is being held in a buffer before being written to memory, the read is satisfied through the buffer contents, & the read is not sent to the DRAM. Set this to Enabled for better performance.

SDRAM Bank Interleave: For best performance set this to 4-bank/way, although lower settings may help improve stability.

SDRAM CAS Latency Time/SDRAM cycle length: This sets the CAS latency timing of the DRAM system memory access cycle when SDRAM system memory is installed. Setting this to 2 will yield better performance, although may be less stable if your SDRAM is not CAS2 rated. 3 is slower & should be used when SDRAM isn't CAS2 rated or you want to improve stability. NOTE - CAS2 can significantly improve performance in many ways.

SDRAM Precharge control: When enabled, all CPU cycles to SDRAM result in an All Banks Precharge Command on the SDRAM interface. Setting this to enabled should improve RAM performance. NOTE - When overclocking, particularly when you have an AGP graphics card thats running at non-spec AGP bus speeds disabling this may improve stability.

Spread spectrum (modulation): set this to disabled. This has to do with EMC (Electro-Magnetic Compatibility) testing. As a result you shouldn't need to enable it at all. Unless, you get intereference as a result. This is similar to radio signals affecting unshielded speakers. Setting this to enabled varies the bus speed a little so that system doesn't emit intereference at the same frequency. This affects performance however.

System BIOS cacheable: set this to disabled. The system BIOS is very rarely accessed when you are using your PC after it boots up.

Video RAM cacheable: set this to disabled. The video card RAM is more efficient than caching it & make your system more stable as well.

8 bit I/O Recovery Time: The lower the setting the better, with N/A being the best. Set it to N/A if you have no ISA bus cards in your system, if you do try setting it to 1 instead. Increase the value to fix problems with ISA based cards.

Softmenu 2/3/Overclocking settings

The following BIOS settings may help you to overclock your CPU. Obviously this can potentially damage your system so be careful. The settings below are from my VT6X4's (Softmenu 2) bios, so don't worry if you don't have some of these settings.

Before you even consider overclocking you need cooling & ideally lots of it. You should consider purchasing a good cooling device. We have a few reviewed here, such as the 3DfxCOOL Alpha P3 125 cooler.

Turbo frequency: This can only be used at 66 & 100Mhz FSB's. This increases the FSB to 68.5 or 103Mhz respectively, depending on what your current FSB is. Essentially its a "safe" overclock, but disable it if it causes problems (unlikely).

Ext. Clock (PCI): Depending on your CPU, your bus speed will generally either be 66, 100 or 133Mhz. The PCI bus operates at a fraction of this, 33Mhz. By increasing the FSB you will also be increasing your PCI bus speed, which can be dangerous & devices may not work properly or your system will become more unstable. The table below shows different Ext. Clock speeds, PCI multiplier & the resulting PCI bus speeds.

Depending on your motherboard you may have the 1/4 multiplier for the PCI bus when 133Mhz Ext. Clock speed is reached. This will drop the PCI bus back to the standard 33Mhz (133*1/4 = 33).

Multiplier Factor: CPU's nowadays are multiplier locked. So this section is pretty much for informational purposes only. To get CPU speed you need to multiply Multiplier by Ext. Clock, e.g. If the multiplier is 4.5 & Ext. Clock is 133 then the CPU speed = 4.5*133 = 598Mhz.

Softmenu 2/3/Overclocking settings

Core voltage: When overclocking, increasing the value for the core voltage may help you attain higher speeds stabily. This will increase heat too though. Don't increase voltage too much however as you may damage your processor.

I/O voltage: Increasing this "might" help to get some of your hardware to run at higher bus speeds, try increasing the value if you experience such difficulties when overclocking your system. Some older motherboards may require you to do this even when not overclocking as they don't supply enough power for, say your graphics card.

AGP/CLK: Depending on your CPU, your bus speed will generally either be 66, 100 or 133Mhz. The AGP bus operates at a fraction of this, 66Mhz. By increasing the FSB you will be increasing your AGP bus speed, which can be dangerous & your AGP card may not work properly. Depending on your BIOS you may be able to select different AGP multipliers (1/1, 2/3 or 1/2). This may help you keep stable while overclocked. The table below shows different bus speeds, AGP multipliers & the resulting AGP bus speeds. Remember, 66Mhz is what it's intended to be.

The 1/2 AGP multiplier is not available on BX based motherboards, only newer ones such as the i840 or VIA Apollo 133  based motherboards.

If you haven't the ability to change your bus speed via the BIOS you can always use SoftFSB to do so. The tables above showing the effects of non-standard bus speeds still applys however.

Load (fail-safe) defaults

Softmenu 2/3/Overclocking settings (Cont.)

Load optimized defaults

Use this option to load optimized BIOS settings for your system. This option is available on the VT6X4. Although it is preferable to see what actually gets changed by making the BIOS changes yourself.

Set password

Use this to set the password that is needed to either enter into the BIOS or to boot the system. If you are the only user of your system you should leave this alone. Entering in a blank field will disable the password.

Save & exit setup

Select this option to save any changes you have made in the BIOS & exit the BIOS to load up Windows, or other operating system.

Exit without saving

Use this option instead of the one above if you wish to exit the BIOS without saving the changes you have made.

Final note

Shadowing/caching. While shadowing/caching can improve performance in some cases, if the area of memory used for the shadowing/caching purposes is written to your system (or progam at least) will crash. BIOS shadowing/caching is particularly worthless as your BIOS is only needed at startup, or possibly when in DOS mode (particularly the videocard BIOS).

Basically your RAM/cache is better used for other purposes where it will improve performance, rather than where it might improve performance.

Conclusion

Hopefully your PC will now be performing better &/or more stabily by modifying BIOS settings. With a bit of luck you may even have managed to overclock your system as well, which would give even greater performance gains.

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