Power Consumption and Performance per Watt
Testing power consumption has become just as important and relevant in recent years as judging performance of these processors.  And unfortunately, testing power consumption has also become a lot more complex than it used to be.  Where as we used to just simply test and idle and a load configuration from the wall, new advancements in multiple-core processors, changes in how power planes are controlled on these CPUs and software complications give us a bit more to think about in our power testing.

Intel Core i7-875K and Core i5-655K Unlocked Processor Review - Processors  76

Intel Core i7-875K and Core i5-655K Unlocked Processor Review - Processors  77

The power consumption of the processors fell right in line with where we expected them be based on their Lynnfield and Clarkdale heritage.  Obviously, because these two processors were tested on a different motherboard than our previous CPUs used there are going to be a handful of watts difference either way. 

Obviously the power consumption of overclocked processors will skyrocket over these as the CPU leakage rates increase but I think it goes without saying that is you are going to be attempting hit 4.8 GHz on your processor you are well aware of the inefficiencies in doing so.


Performance per Watt Measurements

Now I want to evaluate how the different processors tested here relate to each other in terms of performance per watt.  To do this I took the load power consumption of each processor and divided it into the benchmark result to create a new metric like Hz/watt (for Euler3D) or FPS/watt for the games. 

Intel Core i7-875K and Core i5-655K Unlocked Processor Review - Processors  78

Intel Core i7-875K and Core i5-655K Unlocked Processor Review - Processors  79

Intel Core i7-875K and Core i5-655K Unlocked Processor Review - Processors  80

Intel Core i7-875K and Core i5-655K Unlocked Processor Review - Processors  81

Intel Core i7-875K and Core i5-655K Unlocked Processor Review - Processors  82

With the slightly lower power consumption seen in the K-series tests we did this resulted in a noticeable but not dramatic increase in efficiency and performance per watt.

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