Optimizing a PC's BIOS, Part 1

The BIOS is an essential set of routines in a PC, stored on a chip. It provides an interface between the operating system and the hardware, acting as an intermediary between a computer's hardware and its operating system. Without the BIOS, the PC's operating system would have no way to communicate with, or take control of, the hardware.

In other words, the BIOS is a crucial component of any computer. If set incorrectly, the BIOS could slow your customers' computers by as much as 40%. To make matters worse, as new processors and motherboard chipsets are released, BIOS options continue to get even more confusing.

While each motherboard and/or computer manufacturer utilizes a different BIOS, in this Recipe we'll cover the steps involved in optimizing the BIOS on an Asus A7N8X Deluxe. I've chosen this brand and model motherboard because it's so popular with white-box builders. Also, the A7N8X is one of ASUS's most popular models; it's been available for nearly two years and is still sold today for AMD-based systems.

Keep in mind that changing a PC's BIOS settings incorrectly can cause the PC to malfunction. If this happens, a BIOS reset, usually activated by a jumper on the motherboard (easier said then done with many laptops) will need to be performed to return the default (read: unoptimized) "factory settings." Nothing offered in this recipe should have a negative affect on any PC, so please follow each step explicitly.

Also, many large PC manufacturers such as Dell, HP, Gateway and Micron limit the options available to the end-user in the BIOS to reduce support calls. As a result, you may not be able to take advantage of some of the advanced settings in this Recipe on PCs from these major vendors.

Most PCs briefly display a message describing how you can enter "setup." You're allowed only a few moments to press the required key before your operating system starts to load. To enter your BIOS, turn on the PC and hold down, or press repeatedly, the key required to enter setup. On most PCs this is either the DEL key or the F1 or F2 key. If your PC will not enter setup using those keys and/or does not display the message described above when first turned on, you will need to refer to your documentation or contact your PC manufacturer's support.

If you are using a motherboard other than the Asus A7N8X Deluxe, reboot after each BIOS change to ensure that your system functions normally. If you instead make numerous changes before rebooting, and your system will no longer boot, you will not know which change is responsible for the failure. To be sure, reboot after each change.

Main Options

Now go to the BIOS Main Options Menu by clicking on the "Main" tab in the upper left-hand corner.

Just below where you set the date and time, you can also define the specifics of your hard drive(s) and other storage devices installed in the PC. Each time the PC boots, it most likely has to auto-detect and determine what storage devices are installed on the system. While this takes only a second or two on most systems, if you define these specifics rather than use auto-detection, your boot-up will be that much quicker.

To do this, simply select the drive, usually by highlighting it and pressing Enter. Then write down the numbers currently displayed for the Cylinders, Heads, Sectors, and LBA. On some BIOS, you'll also have options for Block Mode as well as 32 Bit Transfer Mode. Change the drive type from AUTO to USER. Then key those numbers and options in exactly as they were displayed. On most modern computers, you will want LBA Mode, Block Mode, and 32-bit Transfer Mode all turned ON for your hard disk drive, even if they weren't before.

If there is no device attached to any one of the four possible settings, select NONE. For example, if you have one hard drive configured as a Primary Master and one CD-RW configured as a Secondary Master, be sure to set both the Primary and Secondary Slave options to NONE.

Advanced Features

Next, select the Advanced tab on the top of the screen to show the advanced options. These options are broken into sub-menus. The first branch is labeled "Advanced BIOS Features."

Is it really necessary to thoroughly test your memory and floppy drive every single time you turn on the computer? Unless you suspect a problem with either one, I see no reason to continually test them with BIOS diagnostics. In this part of the BIOS we'll be able to reduce system start up times by enabling or disabling specific features -- such as those just mentioned -- to optimize the start-up process. Here are the settings:

Boot Virus Detection: Enabled. Sometimes this is located under the Standard or Main section of some BIOS. While boot sector viruses are no longer the major threat they once were, enabling this feature will protect your data should you boot from an infected floppy disk or CD-ROM.

CPU Level 1 Cache: Enabled.

CPU Level 2 Cache: Enabled.

Quick Power On Self Test: Enabled. This will skip the repetitive memory count that occurs when you turn on your PC. It's a very basic memory test that the BIOS performs each time you turn on your PC. Chances are, if you really do have bad memory, this basic test won't catch it anyway.

First, second, or third Boot Device: Set your boot order, and disable any boot device here you do not want to boot from.

Boot Other Device: Disabled, unless you are booting from a network or SCSI card.

Boot Up Floppy Seek: Disabled. It's a waste of time and a noise maker.

Boot Up NumLock Status: Your choice. Some folks like the NumLock on their keyboard activated when Windows starts, while others want it disabled.

Gate A20 Option: FAST. While this feature is made more or less obsolete by Windows XP, I still recommend you leave it on. Older versions of Windows and OS/2 perform better with this setting set to FAST. The only reason I can see to set it to normal would be if you are running DOS.

Typematic Rate Setting: Disabled. Your choice, really. This feature determines how long the keyboard waits when holding down a key to keep repeating it and how fast.

APIC Mode: Enabled. This is the Advanced Programmable Interrupt Controller, which is responsible for multi-processor support, more IRQs, and faster interrupt handling.

OS/2 Onboard Memory > 64M: Disabled. This setting only applies to users running the now defunct OS/2 operating system from IBM.

Full Screen LOGO Show: Your choice. When enabled, the memory count and Power-On self-test are hidden behind a "curtain" of a graphic. For example, when you first turn on a Gateway computer, you might see GATEWAY in big letters across the screen. When disabled, the "normal" initiation sequence is displayed on the screen -- the way all computers look when you first turn them on before the operating system begins to load. Some people prefer to hide the POST screen, while others prefer to always see it.

POST Complete Report: Your choice. This setting, when enabled, will display the results of the Power On Self-Test (POST).

Speech POST Reporter: Your choice. This setting, when enabled and speakers plugged in and turned on, will 'talk' over your speakers at boot time to tell you the status of the POST. The sound quality is a far cry from Star Trek's computers, but some people think it's cool.

Advanced Chipset Features

Overclockers are people who attempt to increase their system performance by raising bus speeds and increasing their CPU speed beyond the speed at which it was sold and designed to run. They also quite frequently need to raise the voltage of these devices, since they are pushing them harder, which also generates more heat.

Overclocking no longer makes the performance difference it used to. It will also void your CPU warranty, could cause complete system failure requiring complete component replacement, and can cause random system instability. For that reason, many of the frequency and voltage settings offered in this part of the BIOS should be left alone or set to AUTO. To make these settings, click on the ADVANCED tab on the BIOS screen.

CPU External Freq. (MHz) : Be sure to set this in accordance with the specifications of your processor.

CPU Frequency Multiple Setting: AUTO.

CPU Frequency Multiple: Be sure to set this in accordance with the specifications of your processor.

Asus should have called this the CPU Multiplier. An AMD Athlon 2600 CPU runs at 2.133 GHz. The CPU processes data at a different speed than the rest of your system. In this example, the AMD Athlon 2600 talks to the motherboard at 133.33 MHz. This is referred to as a Front Side Bus (FSB). Therefore, 133.33 MHz (generally referred to as 133 MHz) is the FSB speed, while the CPU processes data at a multiple of 16 x 133.33 for a total of 2,133, or 2.133 GHz.

Through various testing, AMD has determined -- as have many independent magazines -- that their 2.133 GHz CPU runs as fast (or faster) as an Intel CPU rated at 2.6 GHz. Knowing that most consumers shop looking for large numbers to equate to performance, AMD had to come up with a way to convince consumers that even though their number was smaller, the processors's performance was the same or better than an Intel system with larger numbers. This explains why an AMD Athlon 2600 (as used in this example) actually runs at 2.1333 GHz and not the implied 2.6 GHz.

System Performance: Optimal.

CPU Interface: Optimal.

Memory Frequency: By SPD. Most memory-chip manufacturers include a Serial Presence Detect, or SPD, chip that reports to the computer's BIOS the memory size, data width, speed, and voltage of the installed memory. These settings are determined by the manufacturer to determine the maximum performance and reliability. This is considered a safe, recommended setting. By adjusting these settings yourself, you may be able to squeeze more performance out of your system -- or, if you're not careful, cause your system to constantly crash, not boot properly, or not boot at all.

Memory Timings: Optimal.

FSB Spread Spectrum: Disabled. This feature helps systems pass European electromagnetic interference (EMI) tests. It accomplishes this by constantly varying, ever so slightly, the frequency of the Front Side Bus (FSB). Be warned that enabling this feature with large values can result in Internet connection disruption as well as stability problems if you over-clock your system.

AGP Spread Spectrum: Disabled. The description above applies here as well, except this is for modulating the frequency of the Advanced Graphics Port (AGP) bus.

CPU VCore Setting: AUTO.

CPU VCore: Be sure to set this in accordance with the Core Voltage requirements of your processor.

There are so many processors out there, I don't know if one example would be better than none. Instead, here is a partial chart. The chart shows the name of the CPU, its actual running speed, core voltage requirement, and how hot it can get before failing. (BTW, this last feature is an option I'll show you how to set in part 2 of this recipe.)

Graphics Aperture Size: 64MB or 128MB. This feature controls the size of the Graphics Address Relocation Table, or GART, and the amount of memory address space used for AGP memory addresses. Regardless of how much on-board memory a system's video card has, a setting of 64MB or 128MB is recommended. This will allow the video card to remain optimized in the event an application requires more memory for texture storage, while simultaneously keeping the GART to a reasonable size.

AGP Frequency: AUTO.

System BIOS Cacheable: Disabled. You might be under the impression that all cache is good. Not true. This feature can cause problems such as system crashes if a program tries to write to the BIOS area being cached. This is a great feature to enable for customers who still use DOS.

Video RAM Cacheable: Enabled. Contrary to what its name implies, this feature does not cache the video memory or even graphics data. Instead, it allows you to enable write combine buffers (on modern video cards) which can result in improved graphics and processor performance.

DDR Reference Voltage: 2.6V. This is for setting the voltage of the Double-Data Rate (DDR) memory in your system.

AGP VDDQ Voltage: 1.5V. VDDQ is an enginneering term meaning literally Voltage between Drain and common for Data Quad-band. It refers to how much voltage to supply to a systems video card.

AGP 8X Support: Enable this if the system's video card supports 8X AGP speeds. You must install the Via 4-in-1 drivers to take advantage of this feature, if enabled, on VIA-based motherboards.

AGP Fast Write Capability: Enabled is recommended. This feature, when enabled, allows the AGP device to bypass main memory when performing write transactions from the chipset to the AGP device, increasing performance by as much as 10 percent. However, some games and PCI cards may experience problems with this setting enabled. It is recommended that you experiment with this setting to determine what works best for a particular PC.

This is Part 1 of a two-part Recipe. Part 2 will continue with more advanced BIOS settings, including Integrated Peripherals, Power Management, PnP and PCI Configuration, Security, and Hardware Monitoring.

CAREY HOLZMAN is president of Discount Computer Repair in Glendale, Ariz., and the author of The Healthy PC: Preventative Care And Home Remedies For Your Computer (McGraw-Hill Osborne, 2003).