Saturday, August 7, 2010

Guide to overclocking Intel

Overclocking, here is a widespread term all over the Internet. But all users of computers that we do not all need know the true meaning of the word. Whether to apply ... So precisely, Multi-Hardware you today concocts a guide on everything from the base. Because too often we assume you're supposed to already know your subject, we'll decipher all you, and you'll know everything at the end! Organized in trilogy (Intel / AMD / MAC G3) is the first part devoted to Intel processors, and in particular the Pentium III 500E commonly called Coppermine. Know that our explanations are also valid for the Pentium II [bus: 100MHz] (from 350Mhz), the Celeron I (from 300A) and Celeron II [every 2 with a 66 MHz bus =] and all Pentium III (Katmai, Coppermine type E [bus = 100Mhz] EB and [bus = 133Mhz]). Only the values of the bus changes as appropriate. But room for explanations.

The clock frequency.

First, we attach to understand how established frequency processor. We could summarize this by a simple multiplication:

Coefficient Multiplier x Bus Frequency = Frequency in MHz Processor in Mhz
What I mean by this multiplier value set by Intel and is specific to each processor:
For example, a Pentium II 350 has a coefficient of 3.5 while a Pentium II 450 has a coefficient of 4.5. This is not what determines the CPU power but rather the frequency of the bus.

The bus frequency is determined by the type of processor. Intel defines the specifications of its processors bus speed for each type of processor range. Now we can say that:
The low-end Celeron is occupied by (I and II) and their bus at 66 MHz.
-The middle of the range is the Pentium III E "Copermine" with a bus at 100 MHz.
-The high end by the Pentium III EB "Copermine" with a bus at 133 MHz.
As you can see, it is precisely the frequency of buses is a sign of power! Indeed, the more you'll get a bus, the higher the exchange of data between the processor and memory (RAM) will soon!
That's why you still can put the SDRAM PC-66 or over with a Celeron, but that for a Pentium III EB, you need to put the SDRAM PC-133!
Caution, however, the power of a processor architecture also means: L1 cache, L2 etc ... but this is not the subject! (We will see that another time!)
While we can not choose the multiplier, bus speed is changed by the user. So here comes the overclock!
Summarize thus:
A Celeron 400 will have a coefficient of 6.0 x ------------- 66.666 MHz = 400 MHz.
A Pentium II 450 ---------- ----------------- ------------- 4.5 x 100 MHz = 450 MHz.
A Pentium III 500E ------------------------- ------------- 5.0 x 100 MHz = 500 MHz.
A Pentium III 733 EB ---------------------- ------------- 5.5 x 133.33 = 733 MHz MHz.
Now, America and study the constraints associated with overclocking.

Constraints and risks

First, let's see why overclocking is possible!
Intel chips in its product line. A processor is above all a "simple" piece of silicon.
Now, take for example the case of the Pentium III "Coppermine". In manufacturing, there is not an assembly line by frequency processor. The costs are too high. What is Intel? (But all the manufacturers of processors) As there is only one production line for PIII processors are tested at different operating frequencies. Some therefore face higher frequencies than the other but it is totally random. The marking is done so by the maximum frequency supported with a safety margin. Usually when Intel is selling a Pentium III 650 is that it is stable guarantee for 650 MHz but also a bit more (about 5 to 10%).
But there comes a second factor: the market. As the production is quite random, although Intel has to bow to the demand which is more important for processors medium frequency (600 MHz) than the youngest (1 GHz). This forces the manufacturer to note in Pentium III 550E Pentium III 733EB selling less. And this is when the multiplier is set. But once you buy this processor features famous techniques that are underutilized. This explains that many PIII 550E pass smoothly from a bus at 100 MHz to 133 MHz bus. (550 @ 733).
Just goes to show you that without knowing you may be in possession of a much faster processor ...
For cons, there is a limit to the increase of frequency: First the cache on a processor board also has a maximum frequency of operation.
The processor is unfortunately not a superconductor, its internal resistance produces heat.
Energy flux E => Energy of thermal agitation.
The internal resistance slows the flow electronically. The electrons travel faster in a 900MHz processor scored in marked 600MHz processor, but it has nothing to do with frequency. The quality of random manufacturing processor by its resistance (and therefore the speed at which the electrons move) will determine the frequency of marking. Each electron flow should not be hindered by the trace of the previous flows. It is this trace that is parasites. A 600MHz PIII E will have a strong internal resistance greater than a 900MHz PIII E scored. If an overclocked CPU heats up, it's not because of the speed of movement of electrons (which is determined by the internal resistance), but because at every second the number of flow-mails sent through the processor is more important. To summarize, a 600MHz processor will heat 600 million times per second, whereas if I increase the frequency, it will heat 630 million times per second, which is why the CPU overheating.
The spurious signals generated disrupt the workings of the processor. A solution exists: the increase of the CPU voltage (and / or) the I / O (the Ram voltage and AGP). In the order of 0.1 to 0.3 volts often.
By increasing the voltage across the processor, we try to make the electrons move a little faster, but it creates much more heat. The electronic speed slightly above achieves higher frequencies.
The problem is that once again the heating processor thinks!
That is why many overclockers are a fan of their most important processor. The risk of such warming is "slamming" the processor. It must therefore be vigilant even if 99% of the time the system crash (refutes to boot at this frequency for the processor too hot) and you only have to restore the original frequency ...
For my part, I've never seen a processor "burnt" (unless you do not place a heater on it ... but hey ..) it says there is always a risk.
Fever overclocking led some fans to utlise cooling systems more exotic ... like liquid nitrogen or Peltier effect plates. The result is often very good since in the case of boxes "KryoTech" applied to the CPU temperature is -40 ° C. ..
These are however cumbersome techniques reserved for lovers ... fortunate!

With the increase in bus frequency, you will also have an increased frequency of operation of the PCI and AGP.
Planned to operate at 33 MHz for PCI and 66 MHz for AGP
. Also the SCSI resent this increase. But the newer motherboards to apply a ratio of frequencies "unofficial".
eg for a bus at 66 MHz motherboard uses a ratio of 1 / 2 for the PCI bus (33 MHz) and 1 / 1 for the Agp (66 MHz).
For a bus at 100 Mhz PCI has a ratio of one third (33.33 MHz) and has one of Agp 2 / 3 (or 66.66 MHz)
In some cards apply another ratio for bus> 133 MHz: 1 / 4 for PCI (33 MHz). The problem is to find an AGP video card that supports an AGP bus high. Some maps are deemed not to pose problems (Creative). Otherwise the solution is to buy a motherboard based i815 or via apollo 133A. with a ratio of 1 / 2 for AGP.

What should I do to overclock?

Increasing the bus speed as the only parameter changed. This requires that the manufacturer already on your motherboard that permitted either through the bios (Jumperless ") or through the use of jumper "on the motherboard.
I can not advise you on the first type of motherboard that you avoid opening your box.
ASUS, ABIT, MSI are the pioneers in this field with the P3BF respectively, the BH6 and 6163!
In addition, some motherboards offer a temperature probe to monitor live the CPU overheating! For our example we have taken our reference computer and we'll show you how to transform a configuration "entry level" real beast running!

Here is a direct application. Equipped with a motherboard chipset Bx: the P3BF ASUS, we will have a panel of high enough frequency range from 100 MHz to 150 MHz!
The limitation of our overclocking may come from:
- SDRAM that even if it is "PC-133" can not support frequencies above 133 MHz.
- Our video card: Geforce 32MB AGP SDRam. Because with the increase of central bus is that of the PMA which may reach its limits.
- The heating of the processor.
For the latter, I suggest you re-edit "radiator / processor. This is really to take a radiator quality (we took an" Aqua 600 ") and then to the assembly with a thin layer of thermal paste (10 francs). The conduction of heat will be much improved.
But first!
For those of you who may have a motherboard with jumpers, it will make your test box to open the computer and have the documentation for your motherboard before you. (For the configuration of your jumpers)
When you start your computer it is enough to get into the bios (Button 'Del').
You'll see a menu that will offer "Advanced".
In this menu you can specify the setting of the processor speed (Auto or Manual). Passing on manual, you will have access to different frequencies as possible for the chipset.

One point to observe: ASUS shows the value of the corresponding PCI bus bus frequency chosen. This explains that the bus is 133 MHz twice in fact you have the option of applying or not a ratio for PCI. So to have a PCI greater than 44 MHz or equal to 33Mhz. Needless to say that the more this value is close to 33Mhz and your system will be stable ... Then still in the "Advanced" menu you can also access the "CPU Vcore" setting corresponding to the voltage of the processor.
So I advise you to gradually increase the frequency of your bus without affecting other settings. To test the stability of your overclocking try running heavy applications like openings image> 150 MB in photoshop!
Another method is to compress large amounts of data with a utility like WinZip. Or a walk, Quake II mod ... software can also help you to see the stability of your overclock. And each time your system is resistant to these tests is that you can still increase your overclocking. When the first crash will occur (yes!) It will be time to increase slightly (0.1 to 0.3 V max) voltage processor. Also check that your ram is set by default .... and to push the machine to its limits set your ram to "Case 3" and pass the voltage I / O 3.5 V to 3.65 V. Each time made a series of tests to verify the stability of the whole.
With regard to our test machine, Pentium III 500E has the ability to overclock very high. This one is etched in 0.18 μ and is supplied with 1.6V. This allows the CPU to heat up very little ....

Our results ....
By following what I've mentioned above (but without increasing the voltage I / O), this is not our processor that has limited but ... motherboard! Indeed with a bus at 150 MHz! the Pentium III will always run without any problem! He just had to bring its voltage to 1.70 v! But I can assure you that it would have accepted a higher bus!
At 150 MHz, PCI was found to 37.50 Mhz which is still suporte for PCI cards.
The feat comes from the graphics card that still works perfectly with an AGP bus 100 Mhz!
Before .... and After!
Simply increasing the voltage (0.1 V) was enough to win 250 MHz .....!
Here's how to give a serious boost to your computer ....
Places to performance!


After this overclocking therefore see the gains in terms of pure power!
For this I made a benchmark utility that offers Sysoft Sandra 2000.
This is the benchmark CPU test "directly measures the floating point power (useful in calculating 3D)" Whetstone FPU "and the raw power of the CPU" CPU Drystone.
At 500 MHz:

At 750 MHz:

The gains are not negligible ...
+ 49.85% CPU power.
+ 49.92% in power FPU.

The fact that the bus is 150 MHz speeds up trade with the RAM.
In use, even it feels like: applications open faster, the games have loading times are shorter and even gain valuable "FPS" (frames per second) ... hence fluidity.

Risks: I measured the temperature at 750 Mhz processor, using the monitoring software for motherboard: ASUS PC Probe.
Here are the results:

A temperature of 36 ° C is just normal ... for a non overclocked CPU! This means that our 600 + Aqua assembly thermal paste was very effective. The only thing disturbing is that this processor could reach a higher frequency with another motherboard! But the interest of overclocking is specifically to reduce costs ... satisfied we have a more than respectable score!


Moore's Law (the number of transistor processors doubles every year) is certainly the greatest enemy of the consumer! Then add 50% more power to your computer will allow you to wait before permanently store your computer in a cupboard!
However, it must also be realistic. Currently, a Pentium III 500E is more than enough to run most applications and games. So, this approach will be really useful when you feel that your computer just ...
Currently, overclocking this scale is only valid if you are a true "power user"! Be aware that for many enthusiasts, it became a real sport and the megahertz race is a real drug!
In any case, be careful in your handling and feel free to ask questions about the forum, in the overclocking section. You will find the world to answer your questions and you can even post your best overclocking.

1 comment:

  1. Overclocking is a collection of methods for making components run faster..