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Jerry
Jerry • Jul 14, 2006

What is CPU Overclocking?

This is a question for all Computer Engineers. Can someone explain what is CPU overclocking and how is it done?

I came across this term recently and googled for it. I know that it is used to boost the CPU frequency.

Thanks in advance.

Jerry
pradypop
pradypop • Jul 18, 2006
All processors(for that matter all ICs) are designed to work at a certain clock speed. If you use any clock above the range than you are over-clocking your CPU.

Now, is it good thing to do? Why do people do it? How to do it? and weather it delivers higher performance?

Its not a good thing to do almost always. People do it to sell off a low-end processor as a high-end one, a marketing trick. A 800Mhz cyrix over-clocked to 2Ghz is available in the market which is passed of as a processor which delivers equivalent of a similarly clocked celeron. That's not true. We can over-clock old P1s an P2s by changing jumper or BIOS settings. For latest boards the frequencies are auto selected. Only manufacturer can over-clock these days.

Over-clocking hampers performance of a processor. By over-clocking there's not enough time available for processor to complete an operation forcing it to redo same operation over and over again until it achieves the result. Thus we bring down the throughput of the processor. It also leads to cache-misses i.e. improper reading of data from system cache.

If its OK to clock Intel 2.0Ghz processor at 3.0Ghz, then you can trust Intel to sell the same processor as a 3.0Ghz processor and not as 2.0Ghz. That sums up things for you.
Jerry
Jerry • Jul 19, 2006
thanks

It is now evident that overclocking is not good for my processor as I still have an old Pentium-III. Is there a way to verify that my CPU is not overclocked? My friend had assembled it for me.

Thanks for the explanation, Pradypop!

Jerry.
crook
crook • Jul 19, 2006
jumper settings

As far as I know, the overclocking is simply done by changing the jumper setting. So you could look at the default setting as mentioned in the CPU manual & check the actual jumper setting.

correct me if I am wrong.

Crooook
aashima
aashima • Jul 19, 2006
well...

pradypop
Its not a good thing to do almost always. People do it to sell off a low-end processor as a high-end one, a marketing trick. A 800Mhz cyrix over-clocked to 2Ghz is available in the market which is passed of as a processor which delivers equivalent of a similarly clocked celeron. That's not true. We can over-clock old P1s an P2s by changing jumper or BIOS settings. For latest boards the frequencies are auto selected. Only manufacturer can over-clock these days.
Overclocking means increasing the working frequency of an electronic component, in this case the processor; using a CPU with higher working frequency means better performances. If you obtain a working frequency of 450 Mhz from a processor with default frequency of 300 Mhz, the performance is the same of that obtained with the version at 450 MHz of the same processor; in a few words, if you achieve a specific working frequency with overclocking, you can obtain the same performance of the version having as default the overclocked frequency.

so there is no harm in overclocking as it provides u with better performance with a low performance chip...
Neha
Neha • Jul 20, 2006
hey, didn't know that earlier...gud
aashima
aashima • Jul 20, 2006
crook
As far as I know, the overclocking is simply done by changing the jumper setting. So you could look at the default setting as mentioned in the CPU manual & check the actual jumper setting.

correct me if I am wrong.

Crooook
i tried getting sum information on the jumper settings... cudnt get much link of it... cud u be more elaborate crook?
pradypop
pradypop • Jul 20, 2006
aashima
Overclocking means increasing the working frequency of an electronic component, in this case the processor; using a CPU with higher working frequency means better performances. If you obtain a working frequency of 450 Mhz from a processor with default frequency of 300 Mhz, the performance is the same of that obtained with the version at 450 MHz of the same processor; in a few words, if you achieve a specific working frequency with overclocking, you can obtain the same performance of the version having as default the overclocked frequency.

so there is no harm in overclocking as it provides u with better performance with a low performance chip...
There are many factors taken into account before the frequency of a chip is recommended. Most important of these are the internal bus and response times of the chip.

A chip has bus speed of X bits/sec can only ensure that X bits would be successfully transmitted in a second. Any attempt to pump in more data in one second would corrupt the data. Over-clocking precisely does that.

An interrupt that is generated by a peripheral need to stay alive for a while so that the interrupt is detected. If the signal falls too early than the interrupt is not detected and peripheral fails. Over-clocking can do that.

These are only two examples. There can be hundreds of such examples.

If over-clocking can help, I would clock my 3.0Ghz PIV at 3.0Thz and convert my computer into a super-computer. But the bad news is, things simply wont work that way. Working and default frequiencies are two more words in the jargon list. Most engineers who design boards keep working frequiency at the default recommended frequency.
aashima
aashima • Jul 20, 2006
well...

pradypop
If over-clocking can help, I would clock my 3.0Ghz PIV at 3.0Thz and convert my computer into a super-computer. But the bad news is, things simply wont work that way. Working and default frequiencies are two more words in the jargon list. Most engineers who design boards keep working frequiency at the default recommended frequency.

well there are alwaz certain limitations attached when it comes to enhancement of something and the limitations become even more mandatory when we are dealing with electronic equipments... therz no doubt we can improve our system performance with overclocking but the limitation that rests here is we can overclock a cpu to max 5%. for e.g. a clock with speed of 400mhz can only be overclocked upto 5% to be safe...within this range of overclocking... we can enjoy the +ve results of overclocking otherwise we will have to face the problems enlisted by pradypop...
well a 3.0thz computer cannot be converted to a super computer newaz 😉
crazy
crazy • Jan 20, 2007
Overclocking is the process to speed up of your proccesor. But it is not good for your proccessor. It can harm your hardwares.
Overclocking can done by three ways,
by changing jumper or dip-switch settings or by changing some of the chipset features settings in your BIOS.
The most common methods of overclocking your CPU is to either raise the multiplier or raise the FSB(front side bus).

please correct mi if i'm wrong....
vibhor_one
vibhor_one • Feb 3, 2007
pradypop
There are many factors taken into account before the frequency of a chip is recommended. Most important of these are the internal bus and response times of the chip.

A chip has bus speed of X bits/sec can only ensure that X bits would be successfully transmitted in a second. Any attempt to pump in more data in one second would corrupt the data. Over-clocking precisely does that.

An interrupt that is generated by a peripheral need to stay alive for a while so that the interrupt is detected. If the signal falls too early than the interrupt is not detected and peripheral fails. Over-clocking can do that.

These are only two examples. There can be hundreds of such examples.

If over-clocking can help, I would clock my 3.0Ghz PIV at 3.0Thz and convert my computer into a super-computer. But the bad news is, things simply wont work that way. Working and default frequiencies are two more words in the jargon list. Most engineers who design boards keep working frequiency at the default recommended frequency.
Sir,

It was good to know about CPU overlocking but sir can I do it with my pc. Could this process can enhance my computer.

Regards

vibhor_one
xero
xero • Feb 8, 2007
I guess I don't feel easy, to reply this one after reading the replies..

CPU overclocking is nothing but increasing the clock frequency. I guess by now ev'body know this :smile:

Now the "not known" part..

Overclocking is meant for serious gamers, to get the max power from the processor, though with the advent of hard core GPUs its not required, but still some do.

Overclocking decreases the life of the processor, and the overall system temperature increases.....

As per what i know that, overclocking doesn't require hardware tweaking, bios will be pretty helpful in that scenario unless u don't have an Intel board. Rest assured it does increases the over all performance of the system
One good chip to overclock is the Intel Pentium D 805. Its relatively cheap, and you can push it up to 4Ghz (from 2.6Ghz) without requiring expensive hardware to make it stable, like water coolers or anything 😀

Generally, you can overclock by either increasing the Front Side Bus frequency, the Multiplier, or both. The product of the FSB and the Multiplier will give you the clock cycle of the CPU, which is nowadays in GHz. If the FSB of a processor is rated as 266MHz, and the multiplier is 10x, then your total clock speed would be 2.66Ghz. If you change the FSB to 300Mhz, multipy it by 10x, you just overclocked it to 3Ghz 😀 You can change these settings in the BIOS as mentioned in this thread before, as well as using software than you can run in the OS. Of course, overclocking is an art.. If you go too far with overclocking, you will make the CPU unstable and overheat, causing it to crash even before it finishes booting up. Thus you need to find a good balance and a lot of trial and error.

The enthusiastic overclockers usually invest ALOT of money in cooling equipment, as well as high performance RAM modules, highly rated Power Supply Units and special motherboards which can supply high voltages to the CPU, so you can get an overall performance gains. Overclockers use benchmarking software to see whether the performance gain is worth the extra energy needed. There also a sense of satisfaction that you have a very powerful computer that did not cost you a lot 😉

Xero highlighted that its usually meant for gamers, cause they want to get that extra frame rate to get better performance in games. Plus, you can also overclock your graphics cards too! Nvidia has some good cards for overclocking 😀 But, since there are advanced CPU's these days, most mainstream users don't need to overclock their computers. They are powerful enough to run the usual applications pretty quick!

One more thing to add, sometimes a manufactuer fabricates two chips of the same architecture and performance, but disables some functions of one chip so it be slightly less powerful. They do this so they can sell two different chips for the budget market as well as the high end market using just one type of chip. One method of overclocking the less powerful chip is to find the pins/data lines that the manufacturer had disabled, and fix it using soldering or similar methods. Its possible to get near to the same performance as the high end powerful chip. Of course, this comes at a high risk of damaging the CPU or even the whole computer permanently if you don't know what you are doing. Plus, any overclocking work done on the computer can invalidate your warranty! 😛

Jerry, theres a program called CPUZ (https://www.cpuid.com/cpuz.php) that can identify the type of PIII processor you have. When you find the model name, you can compare it to the original processor datasheet from the Intel website to see if your CPU has been overclocked 😉 Of course, you can always make the BIOS default to see if the FSB or multiplier has changed.
xero
xero • Aug 16, 2007
thnx for the info ash.. !! We owe you for this 😀

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