Overclocking 101

Techniques, tips, and advice for the performance PC enthusiast on overclocking.

Moderator: The Mod Squad

Mobo-fu Master
Mobo-fu Master
Posts: 14276
Joined: Tue Sep 12, 2000 12:01 am
Location: L-1 Bridge

Overclocking 101

Post by Tolemac »

By necessity, this will be a very basic guide to overclocking. Because of the vast differences in motherboards, not all of the steps shown here will be available to everyone. Do the best you can with the board that you have, and above all else, TAKE YOUR TIME AND GO SLOWLY!!!
This is not a process that can be done on the hurry up. It will take time and patience. If you follow this course of action, you will soon be rewarded with "free" MHz. and a faster PC. :wink:

DISCLAIMER!! Overclocking your system WILL stress it and can very easily damage the mobo, CPU, ram, graphics card, etc. If you pursue this any further, you do so at your own risk. Remember, you paid good money for this system. If you fry it, we will sympathize with you, but that is all.

First off, some terms and definitions:

CPU = Central Processing Unit. This is the "chip" that you are going to increase the Megahertz of. Athlon XP, Intel Pentium 4 are CPUs

FSB = Front Side Bus. This is the part of the mobo that you will be dealing with mostly to achieve an overclock of the system. The FSB connects the CPU with the main memory. It's used to communicate between the motherboard and other components in the system.

AGP = Accelerated Graphics Port. This is where your video card goes if it is designed for that slot. It is also a part of the system that will be directly effected by the overclock.

PCI = Peripheral Component Interconnect. This is where you have your other "daughter" cards such as Sound card, Modem, etc. It is also directly effected by an overclock.

BIOS = Basic Imput/Output System. The BIOS contains all the code required to control the keyboard, display screen, disk drives, serial communications, and other functions. It is the first thing that is accessed when you turn the computer on. Most BIOSes are fairly standard, but each has it's own version. Get to know and love your BIOS as you will be spending quite alot of time in it.

Vcore = CPU core voltage adjustment. Not all BIOS or mobos have this, but if your does, then you will need to know about it. This is where you can change the CPUs voltage up or down to help with any stability issues when overclocking.

MHz & GHz= Megahertz and Gigahertz. This is the speed your CPU, memory, AGP and PCI bus runs at. As an example, on the system I'm typing this, my CPU is running at 1470MHz or 1.47GHz., the memory is at 133MHz, AGP is at 66MHz and the PCI is at 33MHz. I currently do not have this unit overclocked.

HS/F = Heatsink/fan combo. Without a good to great heatsink/fan on your CPU, you cannot expect to get a good overclock. The colder, the better!

CMOS = Complementary Metal Oxide Semiconductor. This chip on the mobo holds the info for the date, time and system setup parameters. You need to know where the jumper for the CMOS is in case of system crash.

Now to begin. The very first thing you need to do to successfully overclock your system is to RTFM!!! For those of you not familiar with that phrase, it means READ THE FRELLING MANUAL!!!
No, this is not a joke. If you proceed without RTFM, then you are on your own. You have to know your mobo and BIOS and what they are capable of and NOT capable of. You should also be familiar with the capabilities of your CPU, memory and components. This will help you solve any problems that might arise.

Now that you are familiar with your mobo, components and the BIOS, we may proceed. At this point, it is a good idea to have at least two programs available on your computer. SiSoft SANDRA and 3DMark 2001SE. Both of these have free versions so get those. These programs will help you test the system while overclocking by stressing the various components and giving you immediate feedback as to the stability of the system. It is also a good idea to get Motherboard Monitor as it will tell you what the CPU and system temperatures are.

Go into the BIOS and find the "Frequency/Voltage Control" section. It may not be named that, but it is on most boards. If you've been getting to know your BIOS and RTFM, then you know where this section is and what it's name is. Once there, see how it will let you change the FSB and also if it will let you change the AGP and PCI frequencies or Ratios as it is sometimes called. Each mobo has a Ratio of how the CPU, AGP and PCI interconnect. Standard every day default settings for that is 1:2:4. The FSB is at Ratio 1 or 133MHz (for AMD Athlon and above. Older Classic Athlons, Durons and Intel are at 100MHz), the AGP Ratio is 2 or 66MHz and the PCI Ratio is 4 or 33MHz. For 100MHz systems, the Ratio is 1:1.5:3

When you raise or lower the FSB, you also raise or lower the other buses. If your board allows you to control how the Ratios are set, then that will be a big help in achieving a high overclock. If your board does not have this, not to worry, as you will still be able to overclock it, just not as high.

Starting with the FSB at default, raise it by 2 or 3 MHz and reboot the unit. Allow Windows (or whatever OS you are using) to fully load and then test the system with either the two progs mentioned or one of your choice. If the progs run fine and the unit is stable, then go back into the BIOS and up it 2 or 3MHz more. Continue in this way till the system shows any signs of instability. Once that happens and you have the ability to adjust your Ratios, then do so so that the AGP and PCI buses are as close to default settings as possible. Reboot and test the system again. If stability is achieved, then go for some more MHz.

At some point, you will have an unstable system no matter what the MHz or the ratios are set at. Now is the time to try adjusting the Vcore. Whatever the default is for your CPU, raise it by one or two steps. As an example, on my unit, the default is 1.75v. When I overclock it, I will raise that to 1.775v or 1.80v. DO NOT GO TO THE TOP OF THE VOLTAGE SETTINGS RIGHT AWAY!! You can fry your CPU very easily doing that.

Reboot and retest the system again. If the instability goes away, then you have more than likely reached the highest overclock you can get. If the unit remains unstable, then you will need to try upping the Vcore another notch. If that fails to get the system stable, then back the FSB off by 2MHz and try again.

Once you have found the "sweet spot" of your system, you will need to monitor it for a few days to make sure that the overclock is holding and not causing any stability problems. I test my unit twice a day when first overclocking to make sure that it will not give me trouble and that the system is not being too stressed out. If at any time the unit goes unstable, then either back the FSB off or return the unit to the default settings and let it run at that for a couple of days and try again.

Be sure to check your CPU temps to make sure they don't go above 55*C while overclocking. If it does, then either back it off or get a real heatsink with Arctic Silver III thermal paste on there!

For those of you with an unlocked CPU.
If you have a CPU that can be unlocked and you haven't done so, then read this first: Unlocking the Duron and Athlon Using the Pencil Trick. After you've accomplished that, you will want to see if your BIOS or mobo will allow you to adjust the multiplier. If so, then here's what you need to do. It is better for the system to increase the multiplier than the FSB as now the rest of the system buses will stay at default, yet you will increase the output of the CPU. The multiplier is multiplied times the FSB to give you the clock frequency. As an example, on one of my Duron units, I have a 1.0GHz CPU running at 1.2GHz without changing the FSB. Default FSB on that unit is 100MHz and default multiplier is 10x. So 10 times 100MHz or 10X100MHz = 1.0GHz or 1000MHz. By adjusting the multplier to 12x, I am able to get 12X100MHz or 1.2GHz. Now my unit is 200MHz faster than it was previously, but all of the system buses have not changed thereby giving me a much more stable system.

Play around with the multiplier and FSB to see what you can do with it without changing the other buses too much. Other than that, the above instructions apply as well.

Troubleshooting note:
If you find that the system either is completely unstable or it hangs on you at any time, you will need to clear the CMOS jumper on the mobo. This is accomplished by moving the jumper from it's default setting (usually pins 1-2) on the jumper header and putting the jumper on pins 2-3 for about 30 seconds or so. Do this with the power off!!! Return the jumper to it's default position and reboot the computer. All of the settings in the BIOS will now be back at factory defaults and you will have to reset them to where you had them before it hung or crashed. Do not put the FSB at the same setting as it was when it crashed or it will just crash again!

If you follow the above steps carefully, you should have a nice overclocked system. As I stated at the beginning, this is just a basic guide. If you run into any difficulties or weirdness or have any questions, just make a post in the forums and one of our friendly Mobo Fu Masters will be able to help you.

Have fun with this and remember, Overclocking! It's a way of life! 8)
[url=http://tolemac.net/blog/psychic-healing/][color=purple]The Gift of Healing[/url][/color]
[url=http://www.consciousenergymeditation.com/][color=purple]Conscious Energy Meditation[/url][/color]