Basic Concepts of Overclocking Intel Core i3/i5/i7 CPUs

Third Generation Intel Core CPUs

Ivy Bridge Overclocking is almost identical to Sandy Bridge overclocking. Simply put you only need to overclock the multiplier and not the base clock (BCLK). With these new Ivy Bridge chips, overclocking is a child’s play into experienced hands, thus the whole procedure is a lot easier. For example  there is almost no need to increase the secondary CPU voltages, such as VTT. Even more, Ivy Bridge is more unlocked than Sandy Bridge, because it offers many more memory multipliers and even adds in a second divider so that you can run memory at different speeds in more friendly increments (like 2000 MHz and 2133 MHz). However under air cooling Ivy Bridge exhibits much higher temperatures during full load due to its 22nm process, which will probably only get better though cooling optimizations and better contact between the IHS and the CPU Die.

On Air/Water: When overclocking on air the only two voltages you should need to touch on an Ivy Bridge setup are the Vcore (which you increase) and the CPU PLL( which can be decreased to help temperatures).

TJ Max for Ivy Bridge is 105C, however you shouldn’t go above 85-90C load when overclocking.

What is increasing to increase the power is the current, you cannot control the current (Ampere), but you can control the frequency and voltage.

[toggle title=”Under the hood of 22nm 3D Transistors!”]

Decreasing the size of the transistor can produce some undesirable results. When we reach the 22nm size, we are dealing with some quantum mechanics theories and when we do this we can talk about the Heisenberg uncertainty principle, which basically states we cannot simultaneously know the location and momentum(momentum=mass x velocity) of a sub atomic particle at a given point in time. That means that there is a certain level of uncertainty which must be applied, and we might not be able to know where the electron is at any given moment. If the electron is outside of where it should be, then we have higher leakage. There is an equation where temperature and leakage are related, and while it is pretty complex, it does allow us to analyze certain points easily.

Sub threshold Leakage= A (W/L) (k^2/q^2) T^2 e^((-qV_t)/nkT) In more simplified terms this shows us that leakage increase exponentially with temperature, and that voltage also has a significant impact on increasing leakage. This has been true for almost all microprocessors, however on Ivy Bridge it is easy to see.

We can see that not only is the temperature decrease having a great effect on the power consumption (representative of leakage), but also an exponential one, as at around -60C on both runs we see a leveling off of the power consumption. However as the temperature rises the increase in power is much more than it is when the temperature is lower. This confirms that the leakage on this CPU is very heavy, we can also see that the leakage is being decreased exponentially as we decrease the temperature.


Overclocking the IvyBridge Frequency:

On Ivy Bridge overclocking is done through the CPU Multiplier on a “K” series SKU like the 3770K and 3570K and the multiplier is multiplied by the base clock. When you overclock the base clock(BCLK) you are overclocking the DMI and PCI-E busses as well, so you might damage or corrupt the devices hooked up to these busses such as your HDDs/SSDs and GPUs on the PCI-E bus. That been told, please don’t overclock the Base Clock, but CPU Multiplier instead.

CPU Frequency=CPU Multiplier X Base Clock

Memory Frequency= Memory Multiplier x Base Clock.

With Ivy Bridge, you want to slowly increase the VCore as temperatures will hurt your max OC much more than voltage can stabilize it. Thus, please increase one the multiplier at a time. If you end up with too much heat then the logical thing would be to decrease the voltage, however at this point you can try to decrease the CPU PLL, and if that doesn’t help much you can always decrease the VTT and System Agent (IMC) to levels where they are lower but still remain stable.

With just increasing the multiplier you can increase the clock speeds of the CPU up to about 4.2 GHz with 42×100.00. If you want a set 100 MHz even base clock it is best to set the base clock to 100.00. SVID will stabilize the CPU to about 4.2 GHz but not beyond that, so you will need voltage increase above 4.2 GHz. Pay attention though, that any overclocks above 42x will probably require VCore increase.

As we told you at BIOS Setup page, if you want the best results you should disable power saving options like I have below, however if you want the CPU frequency to drop under idle conditions, you should leave them enabled, but use fixed voltages instead of auto or offset values.

You will also want to set LLC (LoadLine Calibration) for a slight droop, or Extreme for no droop at all. The LLC on these boards is rock solid, and we recommend you to use it.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.