Overclocking Intel Core2Duo platform

[Hardwareman]

This article will explain how to overclock your Core2Duo.

The new Intel processors the summer of 2006 has somewhat changed the situation in this very closed environment.

The specification of Intel was clear: Taking over its place on the high-end market (eroded by AMD with the architecture K8).

Incidentally, the house of engineers have not forgotten the "geeks".

Indeed, early tests conducted by the specialized press, it became clear that this new architecture had a big potential for overclocking, engineers Redmond had even hinted that the specifications made explicit reference to the need to develop a CPU attractive in this area, then to say that the C2D was designed by and for overclockers ...

Enter the heart of the matter
And because it is important to start with something, talking equipment.
A good overclocking, is initially a good motherboard, then the processor of course, and finally, memory.

Prior Condition
Like AMD, Intel uses a frequency base, generated by the chip of the card mere called FSB for Intel, AMD HTT.
The first C2D operates with a 266Mhz FSB, with this initial frequency, which, multiplied by the multiplier CPU, provide a frequency final for the CPU. For example, a E6300, which runs at 1.86 GHz is the result of 266 x 7, or 7 is the coef. processor (multiplier internal CPU, can be increased). But you've probably heard more frequently FSB1066 or FSB1333. These are the names given to the frequencies of 266 and 333 Mhz C2D because of the technology used by Intel today can make transit four times more frequency equal to that at the time of the Pentium 3. This is the famous bus "Quad Pumped", published with the P4 (somewhat equivalent to the hyper transport bus AMD). To simplify the demonstration, this bus is the result of a four-fold increase FSB base of the motherboard. For example, bus FSB1333 is 333 x 4.
You will have understood that to increase the frequency of the CPU, we must increase the FSB, but the problem is that all frequencies are multiples of that frequency base: Bus PCI and PCI Express, but also the RAM, we back further, but you must know that when you increase the FSB without further precaution, increases at the same time all the others, quickly making the PC very unstable.

[Hardwareman]

The choice of motherboard
For overclocking, it is better to buy a motherboard with a header in the future that we want to do.
I do not want to go into details on motherboards builders, chipsets, but the most powerful to achieve a successful overclocking on Intel C2D are:
The P965 and 975X, the new P35, very promising, it manages the FSB1333 native.
For Nvidia: The 680SLI and 650SLI.

All these chipsets, implemented on very good maps, are able to achieve without concerns of FSB 380/400Mhz (I speak here of motherboards whose prices exceed 130 €).

[Hardwareman]

The Processor
The frequency of the processor is the result of the operation FSB x coef, to increase the pace of the CPU, we must increase the frequency of the FSB base, the coefficient is blocked up.
But the factor plays a major role in choosing the processor that you want to dedicate for the overclocking.

Take an example:
Imagine that you are in possession of a motherboard capable of holding a 350Mhz FSB stable.
You start with a E6300 (coef 7), overclocking this way, you get 350 x 7 = 2450 Mhz.
You decide to change and install a E6400 (coef 8), the latter therefore turn to 350 x 8 = 2800Mhz!
You understand the trick?
To overcome a potential weakness of the motherboard about its ability to mount frequency, we must choose a CPU with a high coefficient.
And that is Intel has made a gift overclockers at the end of 2006, were marketed the "small" E4300, and then shortly afterwards, E4400.
Altogether respectively 1.8 and 2 GHz, they operate with a basic FSB200 (FSB800 Quad Pumped) and therefore have a coef. respective 9 and 10.
These processors are offered between 100 and 150 €, they are preferred for a platform dedicated to overclocking.
Indeed, resume the demonstration above, with the E6300 at 2450 Mhz.
Install in a place E4300, you get 350 x 9 = 3150 Mhz!
If your CPU is the frequency, you are above a Core 2 Extreme X6800!, Only the L2 cache (2 x 1 MB for the E4300) will still benefit the X6800.
Of course, all this is only theoretical, because many cards will not be able to reach 350 MHz FSB, as it is possible that your processor gets ever to exceed 2800 Mhz (although it is recognized that the majority of C2D be able to "take" 3 GHz).

[Hardwareman]

The Memory
The case of memory is more delicate.
First, without memory quality it is pointless!
And most importantly, it will depend on the chipset of your motherboard on the one hand and bios on the other.
For example, the excellent P965 RAM calls for a high frequency, because in most cases it is impossible desynchronizing RAM, therefore it is able to collect the increasing frequency.
At Nvidia, 680 and 650SLI have is more flexible in this area, it is indeed possible to desynchronizing memory by setting it at its value certification through an option bios ( "INLINKED" For example, on nforce 650 / 680).
Like the CPU, the frequency applied to the memory is the result of a calculation based on the FSB chipset.
This is the bios which applies a ratio depending on the type of DDR2 it detects (via SPD).
The DDR2-667 (which runs at a frequency real 333Mhz) ratio applied is 5 / 4 for a FSB266: 266 x 5 / 4 = 332.
If you raise the FSB to overclock your processor without further precautions, you also increase the frequency of RAM.
Let us take our example of the FSB to 350.
350 x 5 / 4 = 437 Mhz.
So you say that your RAM will take forever to this frequency, the PC crash elsewhere well before reaching this value.
Hence it is important to desynchronizing memory, or via a lower ratio (case of P965), or by using the appropriate option bios. (ratios are essentially on motherboards based on Intel chipset).
Taking the same example, but with the DDR2-800 (400 Mhz real) and forcing the bios in the ratio for DDR2-667, the frequency of 437Mhz can go with the DDR2-800 of good quality.
With E6400, then you would get a very nice overclocking.
To summarize, with an Intel chipset, take a minimum of DDR2 800.
With a 650/680 Nvidia, you can content with DDR2 667, but not less.

[Hardwareman]

Preparing for overclocking
Enter the bios and switch to manual setting the FSB.
Block the frequency of bus pci to 33Mhz.
Block the frequency of bus pci express 100Mhz.
Turn off all options like "spred spectrum".
Disable support "C1E"
Disable "vanderpool technology" (VT)
Install CPUZ, which is an essential software that allows you to keep up with frequencies of CPU, but especially the ram. http://www.cpuid.com/cpuz.php

Start overclocking
Opt for a ratio of memory that leaves the memory frequency below its value of certification (if you have the DDR2 800, set there on DDR2-667).

Increase gradually the FSB basic step 10Mhz, for example.
Check systematically changing frequencies via software CPUZ, watch especially the frequency of your RAM, do not exceed (or little) the frequency of certification, apply lowest ratios in order to continue if necessary.

Test your PC with software stressful for hardware (Super Pi, OCCT). To detect instability.
When it is manifest, return to the value of FSB previously stable.

If the result you are not satisfied, it will proceed differently: By testing the limits of each of the key elements of overclocking: The FSB, the CPU and RAM.

Once these limits respective is known, we can proceed with a mix of results.
To go even further, we must adjust upwards to the supply voltage components. It will return there in the advanced overclocking, and this will be the subject of another article, perhaps.
Be aware that C2D are able to climb high frequency leaving the Vcore to the original value.
It is recognized that it is easy to earn between 20 and 40% of additional frequencies, depending on your C2D, the margin of increase was greater for CPU frequency and low coef. high.
It is also interesting to get to run RAM very fast, the performance gain can be significant.

Happy overclocking!