Disclamer:
Everything you change in the BIOS is completely at your own risk. I've done all the changes mentioned here on my PC, so the only way anything can get screwed is if you screw it up.
The settings I have discussed here cover different generations of equipment, and some motherboards offer more settings than others, so not all will be available in any one machine and sometimes you may have to apply a little creative thought to apply the wording used here to your situation.
Upgrading System BIOS
Before configuring the existing system BIOS, check the motherboard manufacturers' web site for an updated version. If an update is available and it fixes worthwhile problems then its probably worth installing.
The BIOS Settings
Standard CMOS Settings
Turn off Auto Search for ATA/IDE Primary Slave and Secondary Master and Slave, etc. Mostly they are devices that don't exist. (system boots quicker)
Advanced BIOS Features
Anti-virus protection / Virus Warning / TrendChipAway
Enabled - Provides system protection but slows the PC down.
Disabled - If you are dual booting with another OS using a boot loader such as LILO it is more convenient to disable this or else it complains every time you boot.
Device Boot Order
Set the Hard Disk with the boot partition as the First Boot Device (usually HDD-0) (for security, and system boots quicker)
Boot Up Floppy Seek - Disabled (performance)
Gate A20 Option - Fast
'BIOS Guardian' or 'Flash BIOS Protection'
Prevents software from editing the BIOS, such-as Virii.
- Enabled
- Disabled (when you need to allow software to write to the BIOS, e.g. when flashing BIOS. a modern BIOS may warn you at startup that this is disabled)
Video BIOS shadow / Video ROM BIOS shadow - Enabled (You should always keep this enabled for increased video performance but is virtually unused with a 32-bit OS)
XXXXX-XXXXX Shadow - Disabled (Setting is no longer necessary under Windows 98SE, Windows 2000 and onwards)
Advanced Chipset Features
DRAM Refresh Rate - Match this with the speed of DRAM (i.e. 80ns, 70ns, 60ns)
DRAM Wait State
SDRAM RAS to CAS delay - Lower setting (faster)
SDRAM RAS Pre-charge Time - Lower setting (faster)
SDRAM Page Closing Policy - All Banks (faster than 'One Bank')
RDRAM Frequency FSB Ratio - Auto (Manually adjust the ratio between the Front-Side-Bus and Memory clock speed)
CPU Fast String - Enabled (Optimises the performance of the Intel Pentium 4 when using RAMBUS)
Video Memory Cache Mode - USWC (faster than UC)
SGP Capability - Higher (faster)
High Priority PCI mode - Enabled
SDRAM Data Driving mode
Normal
Strong - Higher memory performance, Disables Error correction.
Memory Early/Delay Write - Auto
DRAM Timing By SPD
Enabled - Automatically adjust settings below using SPD
Disabled - Configure settings below manually
DRAM Clock - Match with the speed of RAM
SDRAM Cycle Time (TRAS, TRC) / SDRAM Cycle Length / SDRAM CAS Latency - Match this with RAM's rating - Lower (faster)
DIMM interleave setting - Bank Interleave - Enable for increased performance/stability
Each SDRAM DIMM consists of either 2 banks or 4 banks. 2-bank SDRAM DIMMs use 16Mbit SDRAM chips and are usually 32MB or less in size. 4-bank SDRAM DIMMs, on the other hand, usually use 64Mbit SDRAM chips though the SDRAM density may be up to 256Mbit per chip. All SDRAM DIMMs of at least 64MB in size or greater are 4-banked in nature. If you are using a single 2-bank SDRAM DIMM, set this feature to 2-Bank. But if you are using two 2-bank SDRAM DIMMs, you can use the 4-Bank option as well. With 4-bank SDRAM DIMMs, you can use either interleave options. Naturally, 4-bank interleave is better than 2-bank interleave so if possible, set it to 4-Bank. Use 2-Bank only if you are using a single 2-bank SDRAM DIMM. Note, however, that Award (now part of Phoenix Technologies) recommends that SDRAM bank interleaving be disabled if 16Mbit SDRAM DIMMs are used. This is because early 16Mbit SDRAM DIMMs used to have stability problems with bank interleaving. All SDRAM modules can now use bank interleaving without stability problems.
System BIOS Cachable
Enabled (for increased performance, but poorly written programs that write to the memory area used for the caching will crash)
Disabled (to guard against USB problems, especially with VIA chipsets)
Video BIOS Cachable - Enabled (for increased video performance. But be careful, disable it if system crashes/hangs because poorly written programs that write to the memory area used for the caching will crash)
Video RAM Cachable - Enabled (for increased video performance. But be careful, disable it if system crashes/hangs because poorly written programs that write to the memory area used for the caching will crash)
CPU Level 1 Cache - Enabled
CPU Level 2 Cache - Enabled
CPU Level 2 Cache ECC Check - Disable (1% performance gain)
System Performance - Optimal (fast memory timing)
PCI Latency Timer - Change only to remedy problems with Sound
SCSI BIOS - Disabled (unless required) (Minimizes Booting time)
Primary VGA BIOS - PCI or AGP (depending upon the video device being used, or which to boot using if two are present)
Reserve IRQs only for ISA cards that specifically require them.
Spread Spectrum Control - Disabled (for increased performance)
PCI to DRAM Prefetch - Enabled (slight performance gain)
Graphics Aperture Size / AGP Aperture Size - 32MB is fine as its mostly ignored
AGP Capability - Set to whatever your motherboard and AGP adaptor support. This setting makes a huge impact on graphics performance.
AGP Fast Write - Enabled (significant increase in video performance if video card supports it, otherwise it can crash the system so disable it if this happens)
High priority PCI mode - Enabled
OnChip USB - Disabled (if you don't use USB) / Enabled (if you use USB)
OnChip USB 2 - Disabled (if you don't use USB) / Enabled (if you use USB)
USB Keyboard Support
Disabled (if you don't have a USB keyboard)
Enabled (if you have a USB keyboard)
OnChip Sound - Enabled (unless you don't need sound or have a separate sound card)
OnChip Modem - Disabled (unless you need it)
Integrated Peripherals
Onboard Serial Port 1
Disabled (unless required)
Onboard Serial Port 2
Disabled (unless required)
Onboard Parallel mode:
Disabled (unless required)
ECP for printer or scanner (version 1.9, if problematic use 1.7)
EPP for parallel port peripheral or if there is DMA clash when using ECP
OnBoard Legacy Audio - Disabled (unless you need it for games as this will disable the game ports)
PnP/PCI Configuration
Plug n' Play OS Installed
Yes - for Plug'n'Play operating systems (Windows 95,98,Me,2k,XP)
No - for non Plug'n'Play operating systems (Windows NT4) or if you need to manually configure IRQs to avoid sharing.
Assign IRQ For VGA - Disabled (but enable this if your video card requires an IRQ (see video card documentation)
Assign IRQ For USB
Disabled (if don't use USB devices)
Enabled (if use USB devices)
Power Management Setup
ACPI / APM - Enabled
(Disabled with Windows 98 and VIA chipsets to guard against USB problems)
For Windows 2000 to use ACPI you need to turn it on before installing the operating system. Don't set the suspend and standby values, leave that to the operating system to manage.
Modem Use IRQ - NA (unless required)
State After Power Failure - Off for a Workstation; On for a Server
Frequency/Voltage Control
Spread Spectrum Control - Disabled (for increased performance)
More things to guard against USB problems (especially with VIA chipsets)
Write Pipeline Cache (FIC Motherboards and others) - Disabled
Chip Performance Speed - Normal
Miscellaneous
For Pentium 4 CPUs with HyperThreading under Windows 2000, turn it Off
