System Setup

Here is a photo of the system itself:

Overclocking

Maximizing clock frequency on the new Haswell series is exactly like overclocking an unlocked Ivy-Bridge CPU. However, this time, users have to deal with two additional voltages, vRing, also known as vCache, and vInput, also known as vRIN.

vRing is responsible for cache voltage. It will help you overclock cache by changing its multiplier.

vInput sets the voltage the motherboard will supply to the integrated voltage regulator in the CPU. The iVR's purpose is to divide the voltage, supplying different components on the die itself. Some of these components are the cores, cache, and IMC.

For our tests, we overclocked by adjusting the multiplier on both processors. The maximum overlocks we achieved were 4.2 GHz at 1.26 V with the Core i5-4670K, 4.5 GHz at 1.29 V with the retail Core i7-4770K, and 4.7 GHz at 1.23 V with our Core i7-4770K ES.

The variance between overclocking potential from one chip to the next is quite large. I have tested more than four Core i7-4770Ks and only the good ES did 4.7 GHz on air with less than 1.3 V. It's also important to mention that the temperatures are different with the same ambient (room) temperatures and cooling methods. Some chips will produce higher temperatures because of the TIM (between CPU die and IHS) and the iVR.

Let us now take a look at the Core i7-4770K ES's overclocking results, since those are higher than with any other CPU I have tested on the Haswell platform.

Here is the maximum frequency we got on air.


Here is the maximum frequency we achieved with the Core i7-4770K on liquid nitrogen.




As you can see, we achieved a maximum frequency of 6 GHz, which is above average when it comes to Core i7-4770K overclocking. Unfortunately, the CPU cold bugged at -110°C, which means that it cannot operate at temperatures below -110°C.