http://www.thetechzone.com/articles/.../overclocking/


Written By: Chris Kim

Introduction

In this day and age, when the term “fast is not fast enough� is the modow by which nearly all hardcore computer gamers live by, thus creating a black hole of never ending process of new processors and videocards always being released. Therefore, new processors and videocards are released by the month�it seems as if there is a brand new processor or videocard chipset every week that comes in by the masses. Even with these fastest chips and videocards out, most hardcore users still demand more and say that the speed from even the fastest chips aren’t fast enough. Hence, they resort to a process called overclocking, by which users make their processor or videocard run faster than the default recommended speed setting. In this day and age, overclocking has become a common practice with all of the newest hardware devices reaching overclocks of up to 50% or higher!

What is Overclocking?

Essentially, this is the process of running the device faster than it is specified to do. Overclocking is an old process that just recently has gone mainstream. Even back in the days of the 286, overclocks of about 1MHz was considered a successful overclock. Now a days, the mainstream overclock is with processors reaching much higher overclocks, in the 30%-50% range with some heavy duty cooling. How is overclocking achieved? Usually, increasing the frequency at which the processor is multiplied or bus speed run from dictates the speed at which processors will run at. In the case of videocards, a simple BIOS hack will allow videocards to run at higher than normal frequencies.

What Does Overclocking Yield?

The basic ability to get more performance out certain products is the main aim of overclocking. Keeping with the saying “fast isn’t fast enough�, hardcore users will push their hardware to the limits by getting their hardware to run as fast as possible by any means necessary. With a successful overclock, the computer system will run stable and exactly the same as it did at the default factory set frequency. This often requires more cooling than stock and increasing voltage on processors and larger coolers on videocards. Since the overclocking improves the speed of both devices, performance improves in accordance to how much the device is overclocked. Sometimes, when overclocked too much, performance can actually degrade, as the processor or videocard is over stressed beyond optimal frequency settings.




How To Overclock Guide


Basic Steps

Exactly how is an overclock accomplished? Simply by adjusting the frequency of either the CPU multiplier or front side bus speed. All common day processors have a multiplier lock, meaning that the rate at which the speed is multiplied by the front side bus is not adjustable. This change came once Intel learned that some crooked manufacturers were relabeling processors that were able to be overclocked and selling them as that processor, increasing profits for them.

Adjusting the multiplier is simple. Just look at the motherboard user manual, and see how adjustment of the multiplier is accomplished. If you have a pre-Pentium II 350MHz processor and it was manufactured prior to August 1998, your Pentium II processor might not be multiplier locked. This means you can adjust your multiplier to overclock and still keep the same bus speed. This was the traditional way to overclock and is much more reliable than increasing the bus speed. This is because adjusting the front side bus also changes the speed at which local buses operate at (AGP, PCI, and ISA). This can pose a problem with some devices in the buses that have limits at which can operate. If you have a processor that was created post-Pentium II 350MHz, August 1998, your processor is multiplier locked and the only way that overclocking can be achieved is by increasing the bus speed.

Bus speeds are an important aspect to keep in mind because it influences the speed at which all devices connected to the motherboard operate. There are three default front side bus settings, 66MHz, 100MHz, and 133MHz. The slowest of the three, 66MHz, was used by Pentium II processors slower than 350MHz and all previous processors starting with the original Pentium line. Today’s Celeron processors still run at this 66MHz front side bus, which is one reason why the Celeron lags so much behind its older Pentium III brother. 100MHz front side bus is which most processors run today, all Pentium II processors 350MHz and up operate at this frequency as do all of the first generation Pentium III processors and some of the newer Pentium IIIs. Only the newest Pentium III processors operate at 133MHz front side bus. Keeping this in mind, the most obvious choices for overclocking are the slower 66MHz and 100MHz front side buses as there are no more standard frequencies beyond 133MHz.

Celeron and older Pentium II processors can be easily overclocked by going up to 75MHz and 83MHz since these front side bus speeds are found on almost every motherboard. Newer Pentium II and Pentium III processors can overclock easier with 103MHz and 112MHz front side bus speeds easily. Of course, anyone can overclock this easily, but most often than not, something else will be required to get an overclock to be successful. Often, voltage adjustment will be required. Increasing the amount of power that the processor receives will give it the little extra power to get the processor to be successfully overclocked. Remember that when overclocking, always move up in small increments. Doing otherwise

How to Improve Chances for a Successful Overclock

Extra Cooling
The number one problem with most overclocks is that the processor is generating too much heat and that is what is causing the processor to be unstable. That is why extra cooling with larger heatsinks, more fans, and better airflow is always vital. Since increasing the voltage of processors greatly increases chances in overclocking, and increasing voltage creates more heat, therefore cooling the processor creates higher chances for overclocking. The best way to start off is by getting a larger heatsink for the processor. Alpha’s heatsinks have always been known to produce high quality coolers. Adding more fans inside the case will help keep everything cool and will greatly improve chances of overclocking.

Manufacturing Process
As newer products come out, more and more heat will be generated because of the higher speed that these products achieve. And to counteract the evils of heat, manufacturers shift manufacturing processes to a smaller micron die size. The smaller sizes of dies create much less heat, hence allowing faster and more advanced designs. The original Pentium II processors were running on a .35 micron die, the following Pentium II, Celeron, and first generation Pentium III processors all ran on a .25 die and all the newest Celeron and Pentium III processors run on a .18 micron die. The smaller the die, the less heat it produces, but the successful production of such hardware declines because using smaller dies means that they are more fragile than their larger brothers.

When shifting processes, many processors, such as the .25 and .18 micron Pentium IIIs can withstand much different speeds. Is the case with a Pentium III 600MHz and a Pentium III Coppermine 600E. They are both running at the same speed, but the 600E is running the .18 micron. Hence, it will be releasing far less heat than the older 600MHz one. So, more overclocking will be available, despite the younger stepping of the newer 600E.

Stepping and Binning
As processors get older and more mature, so do their cores and ability to withstand higher clock speeds. After several processor revisions, processors tend to get more stable, produce less heat, and have higher clockspeeds. The problem is that not everyone on the market wants the top of the line processor, so with the new steppings, manufacturers tend to mark that new processor with newer process and sell it at the slower speed because that is the hotter selling processor, even if it isn’t the fastest processor or most expensive. Hence, the newer, slower processors that are released after the newer processors have been released creates better chances for higher overclocking since they have been binned as a lower class processor.

The rule of nature is that once a new processor is released that processor takes the highest price that the previous processor that was fastest held and the same relationship continues down the line with each processor being bumped down. When the newest processor is released, the new stepping is given to the slower processors, therefore the processor will have a better theoretical speed it can reach. This is why older versions of the same processor will not overclock as well as the newest processor. A Pentium II 300MHz produced in August 1998 will not overclock as well as the a Pentium II 300MHz produced in January 1999. Intel has been known to produce processors that can run much faster than the factor setting, why do they do this? Because not everyone wants the fastest processor, so they mark all their products at a speed that is in high demand and deliver them, this is why so many of the Celeron 300A processors could overclock to 450MHz so easily, they had the new stepping behind them that allowed them to reach these speeds.

Cache Limitations and Speed
Remember that any older processors such as the Pentium II and first generation Pentium III all have cache that is external, off the die of the processor. Because the cache is not directly on the processor, they are limited in how much they can overclock because separate SRAM chips must be used, so as processor speeds increase, so do the abilities of the SRAM chips. These chips are extremely expensive and not very expendable. These chips also tend to dissipate a lot of heat. As a result, the cache is not run at full speed of the processor like on-die cache processors as the newer Pentium IIIs or the Celerons. So the limitations of those older processors are also because of cache, so there are two limiting factors of older processors. This is one reason why the price of newer Pentium III processors are higher than older Pentium IIIs, the on-die chips are much more complex and difficult to design.