The Science behind the 22nm 3D Transistor and how it can help us overclock!

So let me confuse you a bit and then unconfused you by simplifying everything. Now if you don’t know this, decreasing the size of the transistor takes it down to a quantum level. Quantum mechanics is a scary word, but isn’t very hard to understand, in very general terms it deals with all aspect of physics not covered by tradition physics, so it covers physics down to the molecular/atomic level. When we reach the 22nm size, we are dealing with quantum physics, and when we do this we can talk about the Hinesburg uncertainty principle, which basically states we cannot know where the electron will be at a certain point. That means that 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. So we can analyze Ivy Bridge’s power properties in two ways, first we set a constant overclock and a constant voltage, and we take control of the temperature by decreasing the temperature at full load through the use of liquid nitrogen, and we measure the power input. The power input to the CPU will be reflective of the leakage, lower input power can be because of lower the wasted power and thus lower leakage, and the temperature we put on the CPU will be the temperature. We will then do this at another voltage with a higher frequency and see if the trend is affected.



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.

So how can this help me OC? Well keep this in mind, for every degree you can reduce the temperature of Ivy you are decreasing the leakage at a faster rate than at the degree above it, when you do this you are increasing your opportunity for higher frequency at a much faster rate. So always keep pushing at better temperatures, with Ivy Bridge EVERY degree counts more than the degree above it. At around -60C this effect subsides, so phase change would be a point at which the power scaling starts to end.

Page 1 - Introduction	Page 6 - Step 3: OC-Profiles
Page 2 - Ivy Bridge Basics	Page 7 - Ivy Bridge and LN2
Page 3 - 22 Nanometer and Maths	Page 8 - Ivy Bridge LN2 Memory Overclocking
Page 4 - Step 1: Ivy Bridge CPU Overclocking	Page 9 - Ivy Bridge BCLK Overclocking
Page 5 - Step 2: Ivy Bridge Memory Overclocking

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