BIOS Settings - Accessing, CPU, and Memory Timings

Accessing, CPU and Memory Timings

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Now many new computers use a system referred to as UEFI which essentially does the same tasks that the BIOS used to but many people still refer to it as the BIOS.


The BIOS or Basic Input/Output System is the controller that allows all of the components that make up a computer system to talk to one another. But in order for this to happen, there are a number of things that the BIOS needs to know how to do.

This is why the settings within the BIOS are so critical to the operation of the computer system. For about 95% of the computer users out there, they will never need to adjust the BIOS settings of their computer. However, those who have chosen to build their own computer system or tune it for overclocking will need to know how to modify the settings.

Some of the critical things one will need to know are the clock settings, memory timing, boot order and drive settings. Thankfully the computer BIOS has come a long way in the past ten years where many of these settings are automatic and very little needs to be adjusted.

How to Access the BIOS

The method for accessing the BIOS is going to be dependent upon the manufacturer of the motherboard and the BIOS vender they have selected. The actual process to get to the BIOS is identical, just the key that is needed to be pressed will vary. It is important to have the user manual for the motherboard or computer system handy whenever changes will be made to the BIOS.

The first step is to look up what key needs to be pressed to enter the BIOS. Some of the common keys used to access the BIOS are F1, F2, and the Del key. Generally, the motherboard will post this information when the computer first turns on, but it is best to look it up before hand. Next, power on the computer system and press the key to enter the BIOS after the beep for a clean POST is signaled.

I will often press the key a couple times to make sure it registered. If the procedure has been done correctly, the BIOS screen should be displayed rather than the typical boot screen.

CPU Clock

The CPU clock speed is generally not touch unless you are going to be overclocking the processor. Today's modern processors and motherboard chipsets are able to properly detect the bus and clock speeds for the processors. As a result, this information will generally be buried under a performance or overclocking setting within the BIOS menus. The clock speed is handled primarily by just the bus speed and multiplier but there will be lots of other entries for voltages that can be adjusted as well. It is advised to not adjust any of these without heavily reading up on the concerns of overclocking.

The CPU speed is comprised of two numbers, a bus speed, and a multiplier. The bus speed is the tricky part because vendors may have this setting done either at the natural clock rate or at the enhanced clock rate. The natural front side bus is the more common of the two. The multiplier is then used to determine the final clock speed based on the bus speed of the processor. Set this to the appropriate multiple for the final clock speed of the processor.

For an example, if you have an Intel Core i5-4670k processor that has a CPU speed of 3.4GHz clock, the proper settings for the BIOS would be a bus speed of 100MHz and a multiplier of 34. (100MHz x 34 = 3.4 GHz)

Memory Timings

The next aspect of the BIOS that needs adjusting is the memory timings. Typically it is not necessary for this to be done if the BIOS can detect the settings from the SPD on the memory modules. In fact, if the BIOS has an SPD setting for the memory, this should be used for the highest stability with the computer. Other than this, the memory bus is the setting you will likely need to set.

Verifying that the memory bus is set to the appropriate speed for the memory. This may be listed as the actual MHZ speed rating or it may be a percentage of the bus speed. Check your motherboard manual about the proper methods for setting the timings for memory.

Boot Order

This is the most important setting for when you first build your computer. The boot order determines which devices the motherboard will look at for an operating system or installer. The options typically include Hard Drive, Optical Drive, USB, and Network. The standard order at first startup is Hard Drive, Optical Drive, and USB. This will generally cause the system to find the hard drive first which will not have a functional operating system if it has just been installed and is blank.

The proper sequence for the installation of a new operating system should be Optical Drive, Hard Drive and USB. This allows the computer to boot from the OS installation disc that has a bootable installer program on it. Once the hard drive has been formatted and the OS installed, it is important to then restore the boot order of the computer to the original of Hard Drive, DVD, and USB. It can be left with the optical drive first but this will often cause an error message of no boot image found which can be bypassed by pressing any key on the system to then search the hard drive.

Drive Settings

With the advances made by the SATA interface, there is little that needs to be done by users in terms of drive settings. Generally, drive settings are typically only adjusted when you are planning to use multiple drives in a RAID array or using it for Intel Smart Response caching with a small solid state drive.

RAID setups can get quite tricky as you generally need to configure the BIOS to use the RAID mode. That is the simple part of the setup. After that is done, you will need to create the array of drives using the BIOS from the hard drive controller specific to the motherboard or computer system. Please consult the instructions for the controller on how to enter the RAID BIOS settings to then configure the drives for proper use.

Problems and Resetting the CMOS

On some rare occasions, the computer system may not properly POST or boot. When this occurs, typically a series of beeps will be generated by the motherboard to indicate a diagnostic code or an error message may even display on the screen with more modern UEFI based systems. Pay close attention to the number and types of beeps and then refer to the motherboard manuals for what the codes mean. Generally, when this occurs, it will be necessary to reset the BIOS by clearing the CMOS that stores the BIOS settings.

The actual procedure for clearing the CMOS is fairly straightforward but check​ the manual for the steps to double check. The first thing to do is power off the computer and unplug it. Let to computer rest for about 30 seconds. At this point, you need to find the reset jumper or switch on the motherboard. This jumper is moved from the non-reset to reset position for a brief moment and returned back to its original position. Plug the power cord back in and reboot the computer. At this point, it should boot with the BIOS defaults allowing the settings to be redone.