CPU/BIOS Tweak Guide
Posted: February 25, 2000
Written by: Keith "Farrel" McClellan

Introduction

The CPU and BIOS, together, are probably the most important parts of your system. The CPU, or Central Processing Unit, is responsible for handling every command that the computer processes, and by rights could be called the computer all on its own. The BIOS, or Basic Input Output System, controls that processor and keeps it running. Because they are the most important parts of your system, they are also the most important parts to tweak, and in many ways they have the most leverage in that regard.

With that leverage, however, comes responsibility. Messing around with your CPU and BIOS can be a very dangerous affair, and if it isn't handled properly it can cause serious damage to your hardware. If you aren't an advanced computer user, or at least willing to risk your computarial investment, you probably should stay to the tamer BIOS tweaks mentioned within this guide. We at Tweak3D will not take responsibility for any damage that occurs to your system.

As a precaution, before continuing on with the tweaks, write down any settings that you plan on changing. This way, if there is a problem, you can go back to your original settings and hopefully recover your system.

Flashing your BIOS

Flashing your BIOS is the process of upgrading your BIOS by overwriting its EPROM (EPROM is a type of ROM chip that can be overwritten). Flashing your BIOS can increase speed and stability, as well as add new features and greater compatibility to your system. Because it is more difficult to do than upgrading your drivers, I will go over it in detail here.

The first step, of course, would be to reach the manufacturer's website and download the BIOS flashing utility. It is important to download the most current version, because companies will have older BIOSes posted for compatibility reasons. After you have downloaded the file, make a simple boot disk and copy the extracted BIOS files to the disk (yes, you have to decompress them before copying them on the disk). Then boot the computer using the disk and run the flashing utility. When you are flashing, be careful of the following:

Don't turn your computer off until it's done
Don't do it during anytime where there could be a possible electrical disruption
Don't piss on your computer

The last one is just a general rule. If the computer gets turned off during the flashing process (or the power goes out - that means this is a big no-no during a thunder storm) there is a very good chance that the computer will no longer work and you will have to order another BIOS chip from your motherboard manufacturer (if it is socketed) or buy a whole new motherboard.

Tweaking Your BIOS

Tweaking your BIOS is a complicated process with a great number of variables. I will reiterate, write down ALL of the settings you change unless you really feel like directly reconfiguring from the defaults (which is definitely an option) if something goes wrong.

This guide, in and of itself, has to be a little vague, because every BIOS (not to mention every version) has slightly different names for everything. Look for settings that are similar to the ones I have mentioned in this guide. I am using the "standard" Abit BIOS listings wherever I can. However, if you have a different board or even a different version then the things I do may be a little different.

To get into your BIOS, you need to hit the [del] key while the system is posting. If your BIOS isn't accessible via the [del] key, there is probably another key that you need to press (it should either be mentioned on the screen or within the manual). If your BIOS is impossible to get into, or is just a piece of crap, you might want to check out TweakBIOS. It is excessively cool and can really help. It even has some settings that you can't set even with the best of the BIOSes out there -- so it may be worth it for more of us than just people with bad BIOSes.

The first step you should take in tweaking your BIOS is to detect your IDE drives. You should be able to find an option to detect your hard drives within the BIOS. When this is done, set them to the mode specified (not Auto or it will detect them every time!). This will speed up boot time by a couple seconds. Also, if you have the option, do NOT set your floppy drive to Mode-3. This is a Japanese 1.25 Mb floppy format that doesn't apply anywhere else.

Here are some other BIOS settings to look into:

Turbo Frequency - This setting boosts your CPU speed by 2-5% by mildly overclocking your processor. Be careful with this setting, particularly if you are already overclocking, because it could cause some problems with your add-in cards.

Editor's note: Turbo boosts the speed on my Abit BX6 w/ Pentium II 450 (100x4.5) to 464. 14 extra MHz for free! :)

QuickPOST - Enable the quick power on self-test to speed up your boot time. The only time you shouldn't have this enabled is if you suspect you are having a hardware problem that it may detect.

CPU L1 and L2 Cache settings - These features should be enabled by default (unless you are using an original 266 or 300 MHz Celeron without an L2 Cache, in which case the L1 cache will be the only one enabled). If someone disabled them on you, make sure you enable them for a substantial performance increase.

Virus Warning - I personally find this incredibly annoying, but if you have a lot of problems with viruses (hmmm... what have you been downloading?), enabling this can save you a days worth of work recovering your system. You do have a backup, right??? This also can cause some compatibility problems with hardware.

Tweaking Your BIOS Cont.

Boot Up Floppy Seek - This setting is pretty antiquated and should be disabled on most new systems (new being Pentium and beyond). It will shave a couple seconds off of the boot up time and will not effect the floppy drives at all.

PCI/VGA Palate Snoop - This is another antiquated setting that should be disabled unless you have a very old PCI 2D accelerator card.

Video BIOS Shadow - Turn this off. Most video cards have no use for this feature and it will probably only cause problems. Performance shouldn't be affected much.

Shadow C8000 - CBFFF, etc - For the most part, you are going to want to leave these settings disabled. If you do know the exact memory ranges for your add-in cards, however, you may be able to boost performance by applying the appropriate settings.

DRAM Data Integrity Mode - Error Correcting Code mode should be disabled on your system unless you specifically bought that type of RAM. The setting, when used with the right kind of RAM, can increase system stability dramatically.

Shadow System BIOS - Enabling this can possibly give a system boost, so we recommend that you try it out. Most likely it will not increase performance significantly.

Video BIOS Cacheable - This setting should increase system performance as well, if your video card is compatible with the setting. However, most newer video cards will not make use of this feature and enabling it can cause problems.

Video RAM Cacheable - Depending on the system, and how fast the RAM on your video card is, and how much RAM your video card has, this may or may not increase performance. This is a good setting to try with older cards, but if your card has a lot of RAM on it, this setting may decrease performance.

8 & 16 bit I/O Recovery Time - This setting has to deal with how the computer handles the old ISA bus cards. Setting this to 0 or N/A will usually give the system a slight performance boost. Let it be noted that these setting may cause problems with some ISA cards.

AGP Aperture Size - This setting truly depends on the video card you have in your system. Check out our Voodoo3, TNT/TNT2, and Geforce tweak guides for specific information on your video cards.

SDRAM Precharge Control - This should be enabled unless it causes problems with your system.

Other SDRAM Settings - SDRAM settings, such as CAS and RAS, can definitely increase performance if set properly. However, the lower you set them (lower is better in this case), the more likely your RAM is to fail. The default for these settings is usually 3, but if you feel brave, try out the 2 settings. If they make your system unstable, set them back. Remember, setting your RAM to a CAS or RAS rating they are not spec'd for is akin to overclocking them.

Tweaking your BIOS Cont.

Memory Hole - This is an archaic setting and should be disabled.

Passive Release - Disabled

Delayed Transaction - Disabled

PNP OS - This should be enabled unless you are running Linux on your system as well as a Microsoft OS. If you are having problems with Plug and Play, disabling this may fix the problems.

Init Display First - Choose PCI or AGP respectively.

KBC Input Clock - This setting has to do with the Super I/O chip and should be set to 16 MHz.

Overclocking your CPU and L2 Cache Latency

Overclocking your CPU and adjusting the cache latency is one of the best ways to increase the performance of your system, but it doesn't come without its costs. Both of these operations will void any warranty you have on your CPU, and possibly on your computer. Not only that, but it is also quite possible that you could permanently damage your computer -- which can cost big bucks. However, even with those concerns, the likelihood of it causing problems if it is done properly is almost nothing.

If you are of the more conservative type, but still want to milk your processor for all it's worth, lowering the cache latency on the processor is your best bet. The default on most modern processors is a latency of 4, however, on almost any chip that has an on-die L2 cache will be able to hit a latency of one without any trouble. On chips with backside L2 cache like the PIIs, older PIIIs, and the older Athlons, messing with this setting is a little bit more dangerous, and may not be quite as successful.

To perform this tweak, go into the CPU speed selection area in your BIOS. Before you continue, you will need to find out what speed your processor is running at, what its clock multiplier is, and what FSB speed it is running on. Why? Well, simply put, you will need to manually enter the values to be able to mess with the Cache latency. Once you are in the section, set the CPU speed to "User" or it's equivalent, and set the CPU up properly inputting the FSB speed and multiplier. Then go down to the Cache Latency section and change the setting. By default it should be set to four, so you are going to want to set it lower than that.

If you don't have the options to adjust the L2 cache latency in your BIOS, you can download WCPUL2 here.

Overclocking your CPU and L2 Cache Latency Cont.

To overclock your processor, you go to the same section. Make sure you set your FSB multiplier to the correct setting, and then slightly raise the FSB. Then reboot. If it loads up Windows without errors, reboot and raise the speed again. Do this until Windows will no longer boot properly. Then go back, set it one down, and you are done. All you need to do now is test the system and make sure it is truly stable. You may have to increase your core voltage to achieve optimum stability. We have more information on the overclocking process, and testing procedures, in our How To Overclock Your Computer Guide (Part 1/Part 2).

While you are in the BIOS setup, there is another setting that you might want to play with a bit - and luckily for you, it is the only one that won't void your warranty. This setting is Speed Error Hold. Turn it off for a couple of more cycles per second - it isn't much, but every little bit helps. When you have it enabled your CPU will warn you when the speed is set incorrectly (e.g. overclocked).

When you are overclocking your computer or lowering the latency of your cache, you really need to consider cooling your processor. We have several guides on the subject of cooling your system, including our Case Cutting How To Guide. There is some great stuff in there that you can apply to your system. You don't necessarily need to follow our extreme guides, but adding a larger CPU fan and/or case fan will help reduce heat dramatically.

Also, if you choose to overclock, you need to consider what happens to the other parts of your system. One of the biggest culprits, other than your RAM, that can cause a failed overclock, would have to be your hard drive. This is because as you bump up the bus speed, the PCI bus speed is increased. The result is that often times you may lose all the data on your drive, or corrupt system components. We focus on this subject, as well as some other things, in our Hard Drive / Memory Tweak Guide.

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 before, this program allows you easily access your BIOS features from Windows. The program even allows you to access features that your BIOS 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.

Tweak Programs Cont.

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. Download the program here.

WCPUID - This program was written by the same author as SoftFSB. The program gives all the information about your CPU, such as clock speed, family #, L2 cache size, and much, much more. Download the program here.

System Studio - At the point of this writing, this program is still in beta, but from what I've seen, it is turning into a really cool product. And even better, it is hosted here at Tweak3D. Find out more information here.

System Recovery

What do you do if something simply didn't work? Well, if you didn't do any permanent damage (overclocking concern mostly), all you need to do is reset your BIOS to its defaults. Another option would be to just go back and manually reset everything you changed one at a time. And if you are really having trouble, you can always "short-circuit" the BIOS battery (there is a jumper for it) and fix it that way.

Conclusion

Tweaking your CPU and BIOS is one of the best ways to squeeze that extra speed out of your system, and it is definitely worth the time spent on it. Enjoy, and feel free to contact me with your comments and questions.

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All Content Copyright ©Dan Kennedy; 1999