Intel i5-2300 2.8GHz Sandy Bridge CPU Review - Undervolting and Underclocking


Undervolting and underclocking may seem like a strange concept at first, mainly why would anyone try to make your processor work below stock?  Although underclocking may have a more niche usage, testing underclocked configurations help us paint a picture of the relative efficiency of the i5-2300 in its stock configuration.  Undervolting, on the other hand, is a bit like overclocking, but its aim is to maximize the efficiency of the chip at a given frequency.  Where would this become beneficial, you may ask?  Outside of being generally more efficient, and save some money on your electricity bill, the big gains come in the ever-growing folding/distributed computing projects which are often run 24/7/365, and the increasing cost of electricity adds further incentive to keep your chip running at the minimum power it can run at stable.


We will test the i5-2300 to see how low we can volt it, and keeping in mind that power draw is linearly related to the voltage at a given current, we can see how lowering the voltage helps in the power consumption of the processor.  Another aspect sought by undervolters is for passive, quiet, or media HTPCs who either desire minimum CPU cooling needs for acoustics or simply not having the room for higher-end cooling due to space limitations, and undervolting will also reduce the thermal output (thermal power) of the processor as the power load decreases with the undervolt.


Undervolting keeps the CPU frequency the same, which means you don't sacrifice speed, but you attempt to "feed" it the lowest power needed to keep it stable at that frequency.  This means it's using only as much power as it needs to operate stable, and optimizing the voltage is much like overclocking, with testing the boundaries, and then testing for stability.


We will also perform a quick overclock for power, voltage, and performance comparisons to visualize a better relationship between the various tests and relating them to the power required across a wider clock spectrum.

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# Alex 2012-05-31 00:13

Thanks, I really needed this. I moved to a Picopsu and bought a very high efficiency adapter but failed to see that 12V only operates up to 4.5A. Thus whenever I opened a video file, the computer would die. Underclocking solved the problem beautifully, and now I can run two HD videos side by side if I want!