Overclocking is the somewhat unknown and uncommon practice of running your CPU (or other parts) past the speed that it is rated at. An example is running a 1.2 GHz CPU at 1.4 GHz or a 200 MHz CPU at 233 MHz. How can this be achieved? The following description isn't exact, but it captures the basic idea. Most CPU companies create their CPUs and then test them at a certain speed. If the CPU fails at a certain speed, then it is sold as a CPU at the next lower speed. The tests are usually very stringent so a CPU may be able to run at the higher speed quite reliably. In fact, the tests are often not used at all. For example, once a company has been producing a certain CPU for awhile, they have gotten the process down well enough that all the CPUs they make will run reliably at the highest speed the CPU is designed for. Thus, just to fill the demand, they will mark some of them as the slower CPUs.
Beware, however, that some vendors may sell CPUs already overclocked. This is why it is very important to buy from a dealer you can trust.
Some video cards are also very overclockable with some companies selling their cards already overclocked (and advertised this way). The Programs like Powerstrip can often be used to easily overclock the cards.
Also, if you're afraid to overclock your CPU, let another company do it for you! Companies like ComputerNerd sell CPUs pretested at overclocked speeds.
What To Consider:
Do you NEED to overclock? It may not be worth the risk if your computer is running fine as it is. However, if it seems a little too slow and/or you're a speed freak, it may be worth the risk.
How important is your work? If you're running a very important network server, it may not be worth it to put the extra strain on the computer. Likewise, if your computer does a lot of highly CPU intensive operations, you may also want to not overclock. Obviously the most stable computer is going to be one that is not overclocked. This is not to say that an overclocked computer can not be 100% stable because they CAN. If you just use your computer to play games and would like to have a little faster frame rates, then overlcocking may be worth it.
Potential Side-Effects?
The first impression people usually have of overclocking is "isn't that dangerous?" For the most part, the answer is no. If all you do to try to overclock your computer is change the CPU's speed, there is very little chance that you will damage your computer and/or the CPU as long as you do not push your computer too hard (i.e. trying to run a 500 MHz CPU at 1 GHz. Damage has happened, but it's a rare thing. Also, if you start increasing voltage settings to allow your CPU to run at a higher speed, there is more of a risk there.
The best way to prevent damage is to keep your CPU as cool as possible. The only way you can really damage your CPU is if it gets too hot. Adequate cooling is one of the keys to successful overclocking. Using large heatsinks with powerful ball-bearing fans will help to achieve this. How hot is too hot? If you can't keep your finger on the CPU's heatsink comfortably, then it is probably too hot and you should lower the CPU's speed.
Changing the bus speed is actually more beneficial than changing the CPU's speed. The bus speed is basically the speed at which the CPU communicates with the rest of the computer. When you increase the bus speed, in many cases you will be overclocking all the parts in your AGP, PCI slots, and your RAM as well as the CPU. Usually this is by a small margin and won't hurt these components. Pay attention to them though. If they're getting too hot, you may need to add extra cooling for them (an additional fan in your case). Just like your CPU, if they get too hot, they may be damaged as well.
Difficulty Level:
Believe it or not, it's actually quite simple. In many cases all you have to do is change a couple of jumpers on the motherboard or change settings in your motherboard's BIOS.
Recommendations:
Most of today's CPUs are multiplier locked, but you can change the bus speed. As an example, you could run a 1.2 GHz Thunderbird that normally runs at 133 bus (also called 266 because it is "double-pumped) at:
Multiplier * Bus Speed = CPU speed in MHz
9 * 133 = 1,200 MHz = 1.2 GHz = default
9 * 140 = 1,260 MHz = 1.26 GHz
9 * 145 = 1,305 MHz = 1.3 GHz
9 * 150 = 1,350 MHz = 1.35 GHz
Even though that CPU is multiplier locked, you can change the multiplier by connecting the "L1" dots on the CPU itself with a normal pencil (it's just enough to conduct electricity to allow you to change the multipliers). If you do this properly, it is perfectly safe. Here's an article on how to do this.
9 * 133 = 1,200 MHz = 1.2 GHz = default
9.5 * 133 = 1,264 MHz = 1.264 GHz
10 * 133 = 1,333 MHz = 1.333 GHz
Or change both together, like this:
10 * 140 = 1,400 MHz = 1.4 GHz
All you need to do here is use common sense really. For example, you wouldn't want to try to run a 233 MHz CPU at 400 MHz. For one thing, it won't work. For another, that probably would damage your CPU. I would advise starting out low and slowly trying to go higher. If you have a 233 MHz CPU, try running it one step higher, then the next step. Most likely you won't be able to get a CPU like this to run much higher than 300, but that is a possibility.
Be more concerned with changing the bus speed than the CPU speed as that will provide the greatest amount of speed improvement. For example, running a CPU at 250 (83.3x3) would be better than 262.5 (75x3.5) in most cases because the bus speed of 83 is higher than 75. The default for most CPUs is at 66 MHz bus speed. The newer P2's bus speed is 100 MHz by default. Many computers will not have options on bus speeds, but if you get any of the motherboards I recommend, you will have different bus speed options. The higher bus speed you can run at reliably, the better. Depending on what your other components are though, they may cause your computer to crash or become unstable if they can't handle the higher bus speeds. With bus speeds like 133, you have to have higher quality PC133 or PC2100 DDR SDRAM to be able to achieve this bus speed reliably.
Click here to find out HOW to overclock:
