Common Troubleshooting BIOS setup options detailed

There are many settings in the BIOS of the motherboard probably everyone is "familiar", but the familiarity of their names does not represent a complete understanding of their meaning. Last week with a friend to buy machine, in the installation of the author saw that installed in the motherboard BIOS set to set. I asked casually, "Graphics

Aperture size What does this option mean? ". Installed staff answered a "Set memory Size", and then the author asked the meaning of the, only listen to the person said "I do not know what the meaning of the end." God, he doesn't know what it means, he's still helping us! With the above experience, so I think it is necessary to say that the following seemingly familiar, in fact unfamiliar content.

1. SDRAM RAS to CAS Delay

This is used to set the time period (Clock) required to signal from RAS to CAS. When the CPU is to read from memory or write data, must send out a correct address signal, and the address is by row, column staggered, so divided into RAS (column address signal) and CAS (row address signal), because it is first to address RAS, and then address CAs, so there is a delay in the middle, the proposal is set to 2 Clock (2T), so that SDRAM can quickly address the completion of addresses, so that memory performance can be improved, if the system is not very stable after the setup, then change to 3 Clock (3T). Some versions of the BIOS change 2T to fast, 3T to slow, but the meaning is the same.

2, SDRAM RAS pre-charge time

When the RAS (column address signal) needs to be addressable, how long does it take to start the next addressing, which is usually considered the RAS charge time, theoretically the shorter the better. The option value is the same as the one described above, so it is recommended that it be set to 2T (2 clock cycles), which can improve memory performance, and if the system is found to run unstable, then change it back to 3T.

3. Graphics Aperture Size

The meaning of this option is to set how much primary memory the AGP graphics accelerator card can use to hold the material. Because the AGP graphics accelerator card can use the main memory on the host Board to act as material memory in addition to the memory on the card, this option is available in the BIOS to allow the user to decide how much primary memory to allocate to the AGP display card. In general, how much of the main memory to set how much capacity, such as 128MB in the main, then this project can be set to [128MB], set more is not used. Some people may ask, all main memory is used to the AGP graphics accelerator card, the other part of the data is not memory available? No, the AGP graphics accelerator card only borrows the main memory when the material is stored and uses its remaining parts, so you don't have to worry about the system not being able to run.

4. Memory Hole at 15m-16m

Do you want to keep the 15-16MB area in main memory so that the system is compatible with the earlier ISA card. Some early ISA adapters use the address of the main memory area of 15MB-16MB, and if the user does not empty the address in advance (not to reflect physical memory), it will cause a system conflict and result in the inability to use the ISA adapter card.

5. Video ROM BIOS Shadow

Sets whether to image the contents of the VGA BIOS of the graphics accelerator card into UMB (upper memory). Some BIOS has the "video BIOS cacheable" setting, you can map the graphics accelerator card VGA BIOS to the cache; If your motherboard BIOS does not have this setting, then at least the video ROM BIOS shadow is set to Enabled. Because ROM reading speed is too slow, the CPU to directly communicate with ROM is a waste of time, if this is set to Enabled, the contents of the video ROM will be imaged to the main memory of the memory area (from the 384KB part of the 640KB~1024KB, more correctly, 　　Rom is reserved from the C0000 address, since the data is in the main memory, as the shadow of the video Rom (SHADOW), so the CPU can use the image after the "SHADOW RAM" to quickly obtain the video BIOS ROM data. When you set shadow RAM, you do not have to worry about the amount of primary memory that can be used, because the image is using the reserved memory area, which is usually not used in memory, so it does not affect the normal memory usage, so the user does not have to worry about setting shadow RAM Fewer memory can be used.

6, other adapter card BIOS Shadow Set

In addition to the graphics accelerator card, there are other adapter cards also have their own ROM BIOS, such as RAID disk array card, SCSI card, hard disk protection card, and so on, users can also use the adapter card rom the address used to be enabled, Allow other adapter cards to also image their BIOS content into shadow RAM. But here's the problem. Because the Graphics accelerator card is a necessary adapter card for each computer, there is a separate video ROM BIOS shadow option, but other adapter card options are represented as memory addresses, so how do we know which one of the adapter card's ROM occupies? Do you want to open the shadow RAM? The following author provides two methods, so that users do not blindly guess:

Method One: Review the use Manual of the adapter card:

A complete adapter card usage manual should include all the information that should be available on use, so access to the adapter card should be able to know the address of the ROM. For example, the DC-390UW PCI SCSI card for building state technology has a manual that shows the address of its ROM in DC000, at which point we simply set the DC000-DFFFF shadow to Enabled.

Method Two: Use tool program to detect the address of ROM on adapter card:

When the product manual is not documented and you are not aware of the memory address of the ROM on the adapter card, you can use a tool to detect the ROM address of all adapter cards installed in the system, and here I introduce the Phoenix The BIOS Web site downloads the tool program Pnpoprom.exe to detect all ROM addresses in the system. First to the http://www.phoenix.com/products/util.html page to download the Unti-pnpoprom.zip file, this program is mainly used to detect the expansion adapter card ROM information, in the implementation Pnpoprom.exe program, will appear below the screen, we just look at the bottom of the message on OK: here to find two adapter card ROM, address respectively in c000:000 and c800:000, the first address is Graphics accelerator card VGA BIOS address; The second address, which is the address of the SCSI card BIOS, is also the ROM outside the Graphics accelerator card, but you may find that the address that Pnpoprom.exe found is different from the address indicated in the BIOS for Shadow RAM: The BIOS shadow set an address that is 5 digits in number; This program detects 2 sets of 4-digit addresses. At this time we must first detect the program c800:0000, into the BIOS display of the address notation, the conversion is very simple, the first C800 multiplied by 10, plus the following number (in this case 0), you can get the desired address: C800 X + 0000 = C8000. When converting, note that the memory address is a hexadecimal method of calculation, so the so-called [10], refers to the hexadecimal 10, and the addition to the total of 16, can not be computed in decimal (if your ROM BIOS after the number is not 0). We can then map the BIOS of this SCSI card to the DRAM by simply setting the C8000-CBFFF shadow to Enabled.

7, Spread Spectrum

As the operating frequency of the main board increases, the EMI (electromagnetic interference) has an increasing influence on the stability of the system, but it seems to be becoming more and more difficult to reduce the influence of EMI. Therefore, the new host board has designed spread spectrum this function, by extending the spectrum of the way to the most powerful EMI waveform from the peak to the smooth, so as to reduce the high and low EMI waveform fluctuations. However, in some special cases this feature must be closed, for example, there is a clock-sensitive in the system.