BIOS settings

This section of the BIOS looks like Greek to most people. It controls more of the nitty gritty of the system. Below we will look at the settings in this area. Keep in mind that some of these will vary depending on the year and brand of your BIOS.

Virus Warning
This will control the virus detection abilities of your BIOS, if your BIOS has such a thing. It basically monitors the boot sector and notifies you if anything tries to write to it. Award BIOS now incorporates Trend virus detection in their BIOS, so you will see a BIOS option for that as well. You can either enable or disable it, although it may cause problems with some Disk Utilities such as Nortons. Plus, a full anti-virus program is better.

Typematic Rate programming
Disabled recommended. This feature must be supported by the keyboard. If enabled, you have two settings to specify. The Typematic rate delay is the amount of time the system will wait when holding a key down before it will start repeating the value of that key. Set it to 500 for 500ms delay. The typematic rate (chars/sec) is how fast the value will be repeated when the key is held down. Set to whatever you want. 15 is good.

Above 1MB Memory Test
Disabled recommended. This controls whether the POST will test all system memory for errors upon boot-up. This is made redundant by DOS's HIMEM.SYS, so save boot time and leave it disabled.

Memory Tick Sound
Controls whether you hear an audible clicking while the memory is being counted at boot-up. Kinda trivial, if you ask me.

Memory Parity Error Check
Controls whether the memory is checked for errors. This is done by looking at a ninth bit of data which is a parity value. The parity bit is set so that the parity of all bits together is odd. When checked, if the parity of the byte does not have an odd value, then the system issue a Non-Maskable Interrupt, or NMI, and stops. On some boards, you can disable this feature altogether, but enabled is recommended if your memory supports it.

Wait for F1
This controls whether the system will wait for you to press F1 after any error before continuing with the boot process. Disabled is good for faster boot-up or for file servers, but enabled will make sure you see every error if there is one.

Boot Up NumLock Status
Specifies whether the NumLock will be activated on start-up or not.

Numeric Processor Test
If you have a processor with math coprocessor, which all modern processors have, then enable this function. Disabling it means that the system will ignore the FPU, significantly decreasing performance if your processor DOES have one. Disable only with a old processor without an FPU or coprocessor.

Floppy Drive Seek at Boot
Controls whether the Floppy drive A is powered up at boot-up. Disable for a faster boot-up and longer lasting floppy drive.

Boot Sequence
Controls the order in which the BIOS looks for a bootable device on start-up. Depending on your hardware, there may be a variety of options available here, including booting off the ZIP drive or LS-120 (if your BIOS supports this). Most users have this set to A, C. This makes the system look at the A: drive first for a system disk before going to the hard drive. If you are using SCSI drives, the set to A, SCSI.

Bootup CPU Speed
Set to High. If any problems, try Low.

External Cache Memory
Most systems today have L2 cache, therefore it is recommended for most to have this enabled for increased performance. It is common for users to have L2 cache and have this option disabled. This leads to a slower machine. If you do not have L2 cache, then disable this. If it is enabled and you don't have it, the system will probably lock up.

Internal Cache Memory
Enabled for most. This enables any L1 cache on-board your CPU. Most modern CPU's, 486 or higher, have this. If not, leave it disabled.

Fast gate A20 option
A20 refers to the first 64K of extended memory, known as the high memory area. This option controls whether this chunk of memory is used to control all memory above 1MB. In older systems this was traditionally handled by the keyboard controller chip. For faster performance, enable this.

Turbo Switch
Disable recommended on most systems.

Shadow Memory Cacheable
Enable for faster performance. This copies BIOS code to system RAM for faster access. Disable if there are any problems.

Video ROM Shadow
A relic from the past. When enabled, it copies code from the video portion of your BIOS over to RAM for faster access. In old DOS games, this sped up video performance. But, with Windows, it does not help. Since Windows games use API's like DirectX to write directly to the video card bypassing BIOS, enabling this option could decrease stability of your system since games could overwrite video instructions in RAM.

Adapter ROM Shadow...
This is followed by some cryptic memory addresses. This controls whether you want to shadow the ROM on any adapter cards on your system. Because you need to know what card take what memory addresses in order to use this wisely, it is recommended that this be disabled just like Video ROM shadow.

Quick Power on Self Test
This option enables a quicker boot-up by skipping some of the internal diagnostics that would usually take place on start-up. It makes boot-up faster, but also leaves you more susceptible to errors wince some problems will not be detected at start-up.

IDE HDD Block Mode
Enabling this function can speed up IDE drives by allowing multiple sector read/write operations, a feature most modern IDE drives support. For Win 9x, give it a whirl. Under NT, Microsoft recommends it is disabled to prevent data corruption.

Report No FDD for Windows 95
This setting fools Windows 9x into thinking there is no floppy controller installed, thus freeing up that IRQ. If you're on a laptop with no internal floppy drive, you should enable this as well as disable the FDD controller in Integrated Peripherals.

BUS SETTINGS
This section varies quite a bit on your BIOS version and brand.

AT Bus Clock Selection
This setting determines the divider used on the CPU clock to determine the speed of the ISA/ EISA bus. The settings are in terms of a divider, in the form CLK/ x. X is the divider. It is the number by which the CPU clock is divided to determine the ISA bus speed. The CPU clock is the CPU frequency, but the external CPU frequency. This means that, for example, if you have a 486DX33, 66, or 100, you need to put this setting on the external CPU clock of 33MHz. the good thing here is that most modern boards automatically detect this setting for you.

ISA Bus Speed
Same thing, but for PCI.

Bus mode
Synchronous or asynchronous. In synchronous mode, the CPU clock is used above. In asynchronous mode, the ATCLK is used.

Wait States
whenever something is done over the AT bus, it indicates the number of wait states. This, like with memory, helps to have the older ISA cards work with faster systems.

Fast AT cycle
enable this for faster operations using ISA cards, especially video.

ISA IRQ
Used to tell the PCI cards what IRQ's are being used by the ISA cards so that they can work around them. Used for plug-n-play OS's.

Memory Remapping
Disabled recommended.

DMA Wait States
The number of wait states inserted before DMA. Lower the better

 

CASHE SETTINGS


Cache Read Option
Also SRAM read wait state. It controls how many clocks are needed to load four 32-bit words into the CPU internal cache. It is typically caleed "clocks per word". It is usually notated in the m-n-n-n notation, and is limited to CPU's supporting burst mode. 2-1-1-1, 3-1-1-1, or 3-2-2-2 are common. It determines the number of wait states for the cache RAM. The lower the better. 4-1-1-1 is good.

Fast cache Read/ Write
Enable this if you have two banks of cache memory, 64K or 256K.

Cache wait states
As with any wait state, the lower , the faster.Set this to 0 for best performance. For bus speeds over 33MHz, you may need to set this to 1.

Tag RAM Includes Dirty
Enabling this will increase performance because cache RAM is simply written over instead of actually replaced.

Chipset Feature Settings


This section varies quite a bit on your BIOS version and brand, so i will include names from different BIOS versions. Many people try the settings as tests to see if they help. Feel free to mess around, but make a record of what you change, and if there are problems, put it back.

Automatic Configuration
Easiest setting. BIOS determines all of these settings for you.

Slow Refresh
This allows the memory refresh cycle to occur less often, thus increasing performance and reducing power. Enabled is recommended, if your memory will support it.

Concurrent Refresh
This allows both the refresh hardware and the processor to have access to the memory at the same time. Enable this for increased performance.

Burst Refresh
Perform several memory refreshes at once. Increases performance.

DRAM burst at Four refresh
Refreshes memory in bursts of four. Enable for more performance.

High-Speed Refresh
If memory supports it, this allows for faster refresh cycles.

Staggered Refresh
Refreshes are performed on the memory banks one after the other. This means they will not be done at the same time. This reduces power.

Decoupled Refresh
This allows the ISA bus and the memory to be refreshed separately. since refreshing the ISA bus takes longer, this eases up the strain a little.

Refresh Value
The lower, the better.

Read Wait States
Since the CPU is usually much faster than the memory, wait states are used to keep the memory in-tune with the faster CPU and thus avoid parity errors.

Write Wait States
Same as above, for for write. In many cases, the two are combined into one setting, called DRAM Wait State.

SDRAM RAS-to-CAS Delay
Default is to have no delay. CAS stands for Column Access Strobe. DRAM is organized into rows and columns. Each area is accessed through strobes. When a memory access is performed by the CPU, it activates RAS (Row Access Strobe) to find the row containing the needed data. then, a CAS specifies the specific column to show the exact data needed. RAS speed is the speed of the chip, while CAS is half that speed. The delay setting tweaks the delay between the two signals that control the RAS and CAS. The number dictates how many CPU clock cycles the memory needs in order to prepare for another access. A setting of 3 is normal, but decreasing to 2 might speed up performance. As usual, if this results in any instability, change it back to 3.

System BIOS, Video BIOS, Video RAM Cacheable
This setting copies this data into the L2 cache, thus increasing performance. Problem is that Windows hardly ever uses this feature. So, it is recommend that these options remain disabled so as to preserve L2 space.

Passive Release
Controls whether the CPU can read and write to the PCI bus concurrently over the ISA bus. In general, leave it enabled for increased performance. If you are having problems with any ISA cards, though, try disabling it.

AGP Aperture Size
This setting controls just how much system RAM can be allocated to AGP for video purposes. Some say that the more the better, but in reality, a setting of 64 MB should be fine for anyone unless your manual says more.

AGP 2X Mode
A way to manually set the AGP mode of your system. The setting you choose depends on what mode your video card supports.

Spread Spectrum Modulated
Enabling this allows the system to turn off the AGP, PCI, and SDRAM signals when not in use in order to reduce electro-magnetic interference. Award says this can lead to some instability, so it should be disabled unless you're having an EMI problem.
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 
1