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How to overclock a 478

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Apr 28, 2009
How to Overclock

Overclocking is accomplished by adjusting the frequency of either the CPU multiplier or FSB (front side bus) speed in the Bios of the motherboard. All common day processors have a multiplier locked, meaning that the rate at which the speed is multiplied by the front side bus is not adjustable. Therefore to overclock these processors one must adjust the bus speed.

FSB speeds are an important aspect of Overclocking because it influences the speed at which all devices connected to the motherboard operate. There are usually three default front side bus settings, 66MHz, 100MHz, and 133MHz. The slowest of the three, 66MHz, and 133MHz the highest, was used by Pentium II processors slower than 350MHz and all previous processors starting with the original Pentium line. Today’s Celerons run at this 100MHz FSB, which is one reason why the Celeron lags so much behind its older Pentium III brother. 133MHz FSB is which PIII processors run today, P4 processors depending on the level you have, can range from 400MHz to even 533MHz and up operate at this frequency.

Pentium IV processors can be overclocked 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. More often than not, 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 the smallest increments allowable. Doing otherwise could be harmful for the system

Steps to Overclocking

Step 1: On a blank sheet of paper draw various vertical lines spacing them approximately 1 inch apart, and about 4 horizontal lines spaced 2 inches apart. This is the grid you’ll be using to test for optimal configuration. Label the chart from left to right, FSB or Front Side Bus, Crashed, Voltage, leaving the far right box for whatever you wish.

For some reason higher cache, such as a 1.8a 512K 400MHz FBS Pentium 4’s are more successfully overclocked than a 1.8 256K 400MHz FSB Pentium 4’s. So if you have not yet purchased your processor, the “a” higher 512K 400MHz FSB processor should be on your list. If you’re building a system from scratch, use EPOX or ASUS brands, all their boards are very versatile in respect to overclocking.

Step 2: Starting up your system holding down the “DEL” delete key will bring the system into the BIOS. Once in the BIOS browse around using the left/right arrows to change categories, and up/down arrows to browse the current selection… take a few minutes doing this, familiarize yourself.

At the frequency screen set the frequency adjustment to manual, this unlocking the FBS multiplier usually on the far top of the screen. The frequency adjustment also usually has the clock speed reading as hundreds or thousands. Example, 1.8, would read 1800, and 2.0 would read 2000. Some manufacturers have preset settings to automatically overclock the system, ASUS is one. I would recommend this but know how to reset the CMOS of the motherboard first, usually by a jumper or holding contacts together to reset it. If you purchased the motherboard new, then it should come with a semantic, or locate the model and type it into any search engine in a hunt for more info.

Step 3: Using you handy chart write on the next available block the number of the next frequency level. So if the first frequency level is 133, if you using a Pentium 4 it is, then the next frequency level would be 134, then 135, and so on. For every upgrade to the frequency setting restart the computer noting if the startup was successful. If yes, then follow the same instruction to raise the level again. If not then raise the voltage of the processor in the smallest increments available. Restart again and note if it was successful or not. Ideally you should not raise the voltage of the processor more than .2, if you do then you MUST invest in better cooling such as liquid filled heat sinks. Once you have raised the frequency till it crashes and voltage no more than .2 then retain the previous successful frequency, and raise the voltage another .05 to add stability. Restart and run an application such as Si-Sandra to monitor the temperature of the processor, running the application for several hours at full stress. If the temperature rises more than 20% then enter the BIOS and drop the voltage and frequency. Repeat the process until your processor temperature is within the 20% threshold.

Recommended Settings

There are no unique best settings for every system; however I'll try to give you a basic guideline for a successful overclocking. If your Motherboard doesn't support the higher bus speeds than 133, you can still try the rest, get a calculator and figure out the possible combinations yourself remember its Multiplier x FSB = Internal CPU speed.

Bus and Processor speed

The internal clock speed refers to the actual speed that the CPU is operating at. When you go to the store or look up system specs you will see, for example, Pentium 4 2.4Ghz. The 2.4Ghz part refers to the internal operating frequency of the CPU in question. To make this easy just know that is the speed of the processor, 2.4 Giga -Hertz in this case. The higher internal clock of the processor is the faster it processes information and the more you can do with your computer.

The bus speed refers to the actual motherboard and its components. They too run in Giga-Hertz (Mhz) and run together at different dividers, or fractions of the CPU speed. Your motherboard has traces on it, if you look down at a motherboard and you see all those long lines running all through it to different components that are the bus of the motherboard, data paths to all the components. The Front Side Bus (FSB) by definition is the bus that connects the processor (CPU) and the main Memory (RAM). The PCI bus is the bus that connects all the PCI devices (connected to the PCI expansion slots), as well as the Controller for your Hard Drive and CD-ROM. These are the main buses you have to worry about when overclocking. How this all fits together: It takes the FSB speed (which is also the RAM speed don't forget) multiplied by the CPU Multiplier to create the Internal Clock speed. For example a FSB speed of 100 MHz times a multiplier of 24 will equal 2400Mhz or 2.4 GHz. In order to get other bus speeds and try to get different Internal CPU speeds, your motherboard needs to have more FSB option settings. Keep in mind when you do overclock the FSB you are overclocking your memory (RAM) so if you have some modules of some slow cheap pieces of memory they may not like to be overclocked at all. If you buy good brand name memory like Kingston, Micron, you will have a much better chance at overclocking your FSB.

Again, when increasing your FSB speed, you'll also have to consider all the other devices in your system. Just because the CPU runs stable at the higher speed settings doesn't mean you have overclocked successfully. Any of the other devices can stop functioning or start causing problems. You might need to edit your CMOS and lower some of the settings for the RAM and/or Hard Drives to get your system functioning without problems.

It is a fact that by overclocking you increase the chances of system faults, crashes and overall instability, so if avoiding a crash is crucial, consider buying faster Processor or components, rather than overclocking.

Remember for reference:

PCI Bus = 33Mhz
AGP Bus = 66Mhz
FSB x Multiplier = CPU Internal Clock Speed
FSB x Divider = PCI or AGP Bus Speed

More on overclocking?

Some processors are tricky, because versions were released with both 66 and 100 MHz versions. This shouldn't be a problem though, because most resellers/stores will let you know what the bus speed the CPU is.


In order to overclock your system successfully, you need the understand the most important issue involved – Cooling.

Proper Cooling is the MOST important factor in successful overclocking, running a stable system and keeping your CPU in good shape. If your overclocked CPU operates at a higher than specs temperature, it will shorten its life. Other side effects of overheating can be random crashes and unstable system. Generally, today's processors are designed to work between 85 and 200 degrees Fahrenheit and anything outside the temperature range would result in more unstable system and possible damaging of the CPU. Keep this in mind, cooler is better, try to cool your CPU as much as you can, put a big fat heatsink on it with a big fan to help. Just remember the better cooling solution you choose, the better chances for successful overclocking you have.

Things to remember:

Note: Don't put the panel back onto your PC until your done testing the stability of your system.

Turn off and unplug the computer, take off the case, get your motherboard manual. Check the current clock speed and multiplier jumper settings on your motherboard, compare them with your manual, and write them down in the motherboard manual. Most manuals have an area for notes so use it. Check the supply voltage jumper settings on your motherboard, compare them with manual and your CPU marking, and write it down. Change the jumper settings for clock speed and/or multiplier according to your manual for the next CPU speed up from the settings currently used. Double check to make sure everything is ok, and that no jumpers have been forgotten about or bumped off.

Start computer.

Does it reach BIOS setup?

If yes, test the system further and work your PC hard as possible.

No, Turn off computer and change jumper to higher supply voltage according to manual, if possible.

If you still shouldn't reach BIOS setup, forget about overclocking to this speed.

Does it reach full working operation system?

If yes, start your test run by running it for at least a hour. A PC reaches its maximum temp within about 30 min. It's better to occur crashes or lock ups now, than coming across them when it counts!

If no, try another setting or check your cooling, you also can try some more conservative memory timings in the BIOS setup. This means increasing the wait states or the read/write cycles; but don't forget to check later if you gained speed by trying some benchmarks, cause there's no point in overclocking if your memory access is getting slower.

If everything works well - congrats, if not, try another setting, check cooling.

Don't change supply voltage unless you have to. It only makes the chip hotter.

Don't ever forget: cooling is most important key to Overclocking!


Additional 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. It is VERY important that you monitor temperature levels, mainly the processor. That is why extra cooling with larger heatsinks, more fans, and better airflow is always imperative. 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 is by getting a larger heatsink for the processor. Adding more fans inside the case will help keep everything cool and will greatly improve chances of overclocking.

Processor Life and Market

As newer products come out, more heat will be generated because of the higher speed that these products achieve. And to counteract the heat, manufacturers shift manufacturing processes to a smaller micron size. The smaller sizes of dies create much less heat, in conversely, faster and more advanced designs. As processors get older, so do their ability to be Overclocked and withstand higher clock speeds. After several processor revisions, processors tend to get more stable, produce less heat, and have higher clockspeeds. Customarily once a newer processor is released that processor takes the highest price than its predecessor. 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.

Final Thoughts

Some important factors for successful overclocking

CPU Cooling - Your CPU Heatsink/Fan might do the trick, but it's very likely you'll need a top quality combo. Another, often overlooked fact is that a simple Thermal Compound (from Radio Shack) applied between the heatsink and the CPU can provide for much better heat transfer and cooler Processor.

Case Cooling - The temperature inside the case will also increase, as a result of overclocking, heating all of the devices and possibly increasing the chance of a crash. For ATX cases, I'd recommend an additional intake fan and exhaust fan. The size of the case as well as the placement of the cables inside will also affect its cooling, get rounded cables if you can for best air flow in the case and use air filters in front of the intake fans and vents, keep your case cover on for correct airflow and to reduce dust buildup (dust is an important enemy, it acts as an insulator keeping your hardware even warmer). For proper airflow, a simple rule might help reduce heat in your case even further, just install one more exhaust fan than your intake fans - it's more important to remove warm air from the case, than to blow cold air in.

Quality Components - RAM, Hard Disks, Video Cards all can stop functioning at higher bus speeds, quality components are of course less susceptible to failure under stress. Also, well built, brand name motherboards can definitely make the difference between success and failure. Asus and Epox are two well known very overclockable, easy and friendly motherboards.

Monitoring Software

There are certain software packages out there that help you monitor CPU & motherboard temperature, as well as fan speed. These software utilities can either show readings on demand, or they can be left running in your system tray, displaying temperatures and warnings... These utilities rely on new motherboards with Temperature sensors built into the motherboard. Most high-end motherboards manufactured in the last few years have this capability, some even have the temperature and fan speed readings in the BIOS as well.

Motherboard Monitor -Motherboard Monitor (MBM) is a tool that will display information from the sensor chip on your motherboard in your Windows system tray. MBM supports a wide range of Chipsets & Sensor Chip combinations.

WCPUID - WCPUID is a program that displays detailed information about the CPU in your system.

This overview guide is just that, an overview guide to introduce you to the concept of overclocking. Nowadays overclocking is almost a science, there is so much to it, I could get very detailed on all these topics I've brought up, and there are even some others I haven't mentioned. Good Luck!