I've had so many requests in the past to write a CPU and motherboard tweak guide, including overclocking, BIOS tweaks, etc. Finally I decided to take the plunge and get this guide started. Please read carefully, and take caution. Some of this information is way over the head of beginners. I take no responsibility if you fry your computer because of something you read wrong or misunderstood. Although this guide was written with 440BX motherboards in mind, most of these settings are universal and can be used on almost most any chipset. This guide will tweak only those settings which I believe from personal experience and observation offer the best increases in performance.
Write down any old BIOS settings you are going to change!
BIOS Tweaking
This section is going to be a little vague because there are so many variations in every BIOS that it makes it impossible to cover them all. Therefore you must search for some of these settings. If they do not exist, look for options are very similar. If you still can't find the setting, give up and look at the next setting. I recommend you move through these a few at a time... this way you can determine which will work best together with your system.
To enter your BIOS setup, when booting up your computer hit "delete" or the key mentioned in the first screen when you turn on your computer. It will usually say "Press DELETE to setup" or something similar. If your BIOS is inaccessible or you cannot find a way into it, you should definitely download TweakBIOS. This program will not only make accessing your BIOS 100x easier, it will even let you access parts of your BIOS you could not before. Download it here.
Warning for TNT users - You may notice that some of these settings contradict what is stated in the TNT Tweak Guide or Voodoo3 Tweak Guide. Try both settings and report to me your results. This is the best way to keep the guides up to date with the latest drivers and performance issues.
First and most obvious, are the settings that should be enabled by default, but may have been disabled by someone fiddling with the BIOS.
Turbo Frequency - Increases clock speed by 2.5% to 5%. This setting can cause problems because it sets the CPU clock speed higher than it was supposed to be. However, if it works without problems it can lead to a fair performance increase for all programs. Not all motherboards have this option.
Quick Power On Self Test (POST)- This will speed up the POST (the test that runs when you first cold boot a computer). It should be enabled to shorten boot times.
CPU Level 1 (L1) Cache (also called Internal Cache)- This feature should be enabled by default, but some people may have entered their BIOS and disabled it. Enabling will activate the small, on-die cache included with your CPU. Disabling this will result in a large performance decrease, but may possibly increase chances of overclocking success. I believe that everyone should leave this enabled.
CPU Level 2 (L2) Cache (also called External Cache)- This feature should also be enabled by default, but some people may have entered their BIOS and disabled it. Enabling this will activate your external, L2 cache. This cache runs at 1/2 clock speed on Intel Pentium II CPUs, full clock speed on Intel Celeron (A) CPUs, and various speeds if external. (common with Socket-7 motherboards) Disabling this will result in a large performance decrease, but will increase chances of overclocking success. Only disable if you want to overclock and you believe the limiting factor is your L2 cache. The original Intel Celeron 266 and 300 had no L2 cache.
Virus Warning - Not much of a tweak, but definitely a good thing to have enabled. This will warn you when programs are attempting to access your boot sector or partition table. This can help you stop a virus before it's too late. However, this option can cause problems with several programs, especially during installation. Disable if it gives you any problems.
The next group of settings are questionable. They will vary with almost any PC and should be experimented on.
Boot Up Floppy Seek- Enabling this feature will cause your PC to activate the floppy disk drive and search for a 1.44 MB diskette. This causes a 1 to 2 second delay and should therefore be disabled.
PCI/VGA Palette Snoop - This feature will fix problems with certain video cards. Most people should leave this disabled. Only enable if your video card manual informs you to do so.
Video BIOS Shadow - This feature will "shadow" (or copy) the basic BIOS functions of your video card to memory in order to keep them present at all times. The CPU then reads those functions much quicker than before. This leads to a large performance increase when enabled. Disable if your video card manual tells you otherwise or you see a performance drop.
Shadow C8000 - CBFFF, etc - This will shadow memory ranges of interface cards. Only shadow those addresses which you think are using a card. If you're not certain, experiment with these settings and test performance before and afterward. This is a section that you must thoroughly investigate, just like Video BIOS Shadow.
DRAM Data Integrity Mode - This option allows you to choose between ECC and Non-ECC memory. Most machines now use Non-ECC so choose this option and continue down the list.
System BIOS Cacheable (also called System BIOS Shadow)- This will copy your main BIOS code to RAM and increase performance a great deal if enabled. However, this can cause problems with certain video cards and or memory conflicts. Test both settings and decide which is best for you. If you see no problems with it enabled, leave it on for a nice performance increase.
Video BIOS Cacheable - This is the same as above, only relating to your video card's BIOS instead of your motherboard BIOS. If you see no problems, this will give a large performance increase for any video intensive applications when enabled. Disable if you encounter problems or performance decreases. Test both settings. Consult your video card manual for more information.
Video RAM Cacheable - Enabling this will cause the CPU to cache all reading and writing from your video card's RAM. Enabling this will usually result in a performance increase. Just like all settings, test both methods and decide which is best for you.
8 Bit I/O Recovery Time - This option sets the wait time that is added to an 8 bit ISA instruction originated by PCI. Your motherboard should already be set to the default value. Increasing this value will lengthen the delay. Decreasing will shorten the delay. Setting this value to 0 or NA will remove the delay. This is for optimal performance but may cause some problems.
16 Bit I/O Recovery Time - This option sets the wait time that is added to a 16 bit ISA instruction originated by PCI. Your motherboard should already be set to the default value. Increasing this value will lengthen the delay. Decreasing will shorten the delay. Setting this value to 0 or NA will remove the delay. This is for optimal performance but may cause some problems.
AGP Aperture Size - The AGP aperture size specified in your motherboard is the maximum available memory to an AGP card. The default is probably 64 MB. Setting this higher than your system memory may result in poor performance or excessive memory usage. Try setting this value to anywhere from 25% to 100% of your memory, unless otherwise specified in your video card manual.
SDRAM RAS# to CAS# Delay, SDRAM PreCharge Time, SDRAM CAS Latency Time - These options vary greatly from motherboard to motherboard, so I'm going to have to be vague here. Setting this to "fast" or a lower number will result in better performance. Setting it to "slow" or a higher number will result in lower performance. This can cause problems with many types of ram so test different settings before deciding on a choice.
CPU Warning Temperature - If your motherboard supplies a CPU temperature sensor, you will have this option. Enabling will result in an alarm when your CPU reaches a certain temperature. This is very valuable for overclockers or anyone with a hot PC.
Other Settings... - There are still many other little features present in a BIOS you can explore and gain performance from. Here are some tips I can share: Anything that says "Maximum Performance" will set the feature to be enabled at the cost of compatibility. These can usually benefit performance but often create problems. Observe with caution. Also, anything that says "slow" can be changed to say "fast" or even "turbo." Just as above, these will often create more problems, but will increase performance. The last tip I can give you for tweaking your BIOS is to not have fear of messing things up! The BIOS is one of the safest items to tweak because restoring default settings is easy.
Tweak Programs
I recommend these programs for users looking to take advantage of the "tweakability" of their motherboard and CPU in order to gain performance. Make sure to check them out.
TweakBIOS - Mentioned above, this program allows you easily access your BIOS features from Windows. The program even allows you to access features that your CMOS setup won't allow you to alter. There's one downside though.. it will not save features unless you register. Read more at the TweakBIOS homepage or download TweakBIOS here.
PCIInfo - A freeware utility written by the person that wrote TweakBIOS, this little program will list specific details about devices on your PCI and AGP bus. This will list the vendor's name, type of device, what IRQ it takes, if it supports 66 MHz bus, if it can use AGP 2X, the latency timer set for it, whether or not it is capable of bus mastering, and what type of bus it is using. It is definitely a valuable program for a person looking to tweak their system or a person looking for detailed information. Read more about it here, or download it here.
PowerTweak - PowerTweak is an excellent program that will optimize your processor and chipset. This program does wonders for most machines, and can boost performance across the charts. Read more about it here.
Hmonitor - Hardware sensors monitor is another program nobody should be without. This program is one of the best free hardware sensor programs that allows you to check the temperature of any component on your computer with a sensor. It also has alarms that can be set when the temperature goes too high and even has built in software cooling. (Uses idle CPU cycles to decrease utilization; which really works to decrease the heat) You can even set the software cooling to automatically start when a certain temperature is reached. Read more about it here or download the latest version here.
CpuIdle - CpuIdle is a fairly good program that allows the CPU to cool down in between idle cycles. I have seen this program work well in some cases, poorly in others. Either way, it's worth a shot as a free cooling solution. Read more at the page here or download the program here.
SoftFSB - As far as overclocking programs go, nothing even comes close to SoftFSB. This free program allows you to change your FSB (front side bus) speed on the fly from Windows. Yes, change your clock speed from Windows at any time! Not all motherboards support this program, but many do, and work very well. Read more here or download the program here.
WCPUID - This program was written by the same person as SoftFSB. The program gives all the information about your CPU, such as clock speed, family #, L2 cache size, and much, much more. Read more about the program here or download the program here.
Flashing your BIOS
If you are experience incompatibilities or odd performance issues, make sure to check your motherboard's homepage for the latest BIOS flash. Flashing the BIOS is very simple. You simply create a boot disk with the flash utility and ROM data. Reboot your computer from the disk. At the DOS prompt, run the program as specified. This will flash your BIOS. After restarting your computer, you're ready to go.
If you cannot find your motherboard's website, look in the manual that was included with the motherboard. The URL of the motherboard manufacturer is usually listed either on the front/back cover, or toward the very back of the manual. If you cannot find it, look at the table of contents in the front of the book and search for "Technical Support." The URL will be listed for the website and BIOS updates.
Overclocking your CPU
One of the most popular and efficient tweaks that can offer huge performance increases is overclocking your CPU. While this process is believed by many to be risky and dangerous, it's actually a fairly safe process. I have never seen a CPU failure caused by overclocking (although I'm certain it's happened before to many people).
If you're ready to try and overclock your CPU, make sure to consider the following:
Cool your CPU, using either a large fan, multiple fans, or CPUIdle. The most efficient method (but most risky) is to use thermoelectric cooling devices (peltiers) which can cool your CPU to sub-freezing levels. This, however, can lead to condensation and shorting of the CPU. Also, make sure to MONITOR the temperature if you plan to overclock. This can be done with HMonitor, listed above under "Tweak programs."
Increasing the bus speed is more efficient than increasing the multiplier for most machines. This is because many newer chips have a locked or maximum clock multiplier. Make sure your AGP clock multiplier is 2/3 if you plan to use bus speeds higher than specified by your hardware. (e.g. 83 MHz, 112 MHz) Also, consider that very high bus speeds may have negative effects on even the least obvious hardware, such as hard drives. For more information on this, read the Hard Drive Tweak Guide.
Don't be afraid to increase the voltage of your CPU in order to achieve higher speeds and greater stability. Note that this can lead to even more heat, so make sure you're monitoring the temperature and providing adequate cooling. For more information on increasing CPU voltage with Slot 1 CPUs, read this article over at 3Dhardware.
Read about overclocking before attempting to try it! Some people just jump into their BIOS or jumpers and start increasing the speed. I highly recommend that you read thorough overclocking guides like this one, over at FiringSquad. Other kick-ass overclocking sites include HardOCP and BXBoards.
Recovering from Tweaking
If you had little success tweaking your BIOS, motherboard, and/or CPU, you can always recover your original settings. In your BIOS setup, there should be an option called "Restore Setup Defaults." Choose this option, then change back any settings you wanted to use.
To undo any tweak programs, simply uninstall them. This can be done from the Add/Remove Programs section of your Control Panel. Usually this will fix problems.
Conclusion
Tweaking your motherboard and CPU will bring performance and extra kick back into your machine. Sure it may be time consuming, but it's definitely worth it. Good luck with your tweaking efforts! Don't forget to share your results with us, and check out the many other tweak sections @ Tweak3D.
Booting CD Rom System Cleanup CPU & Motherboard Hard Disk Sound Card
Modem Monitor Mouse System Enhancements Windows Shell
Some part of this document is taken from www.tweak3d.net and www.pcguide.com.
