What is the difference between undervolting and overclocking?

Ajinkya Datalkar May 21, 2013

What is the difference between undervolting and overclocking? How does each impact performance?

  1. Pratish Rao
    May 23, 2013 at 11:56 am

    Undervolting is done in order to conserve power, particularly in laptops and other mobile devices, where energy comes from a battery and thus is limited......................................

    overclocking is to increase the operating speed of given hardware. The trade-offs are an increase in power consumption and fan noise, the system can become unstable if the equipment is overclocked too much, and the risk of damage due to excessive overvoltage or heat generation.

  2. Réy Aétar
    May 22, 2013 at 7:28 pm

    one is the opposite of another overclocking increases the clock rate beyond what is set by the oem where as undervolting does Underclocking

    • DalSan M
      May 22, 2013 at 8:21 pm

      Undervolting is not directly related to underclocking. One has to do with voltage (i.e. 1.5v down to 1.0v), the other deals with processor clock speed (i.e. 3.0GHz down to 2.4GHz), respectively.

    • Réy Aétar
      May 22, 2013 at 9:17 pm

      yes so undervolting leads to underclocking

    • ha14
      May 23, 2013 at 3:51 pm

      well you can undervolt without underclock, but if during undervolt the cpu overclocked then this can cause problems. Combining undervolt and underclock you can gain lot of battery savings. But this all depends on how the laptop/pc is used and cpu, underclocking a pc/laptop while using it heavily is not recommended.

  3. Oron Joffe
    May 22, 2013 at 11:39 am

    There are several good answers above. The only thing I'd like to add is that overclocking means running the CPU at a higher speed. This *often* (but not always) requires increasing the voltage to the CPU, increasing power consumption and heat output, and reducing component life.

    Undervolting *on its own* is exactly as DalSan explains, a way to reduce power consumption and extend the CPUs life without any change to speed.However, you can also underclock, which may allow you to undervolt even more, albeit at the price of lower CPU speed.

  4. Rajaa Chowdhury
    May 22, 2013 at 6:04 am

    Also kindly refer to this MUO article recently published by Kannon Yamada : //www.makeuseof.com/tag/how-undervolting-decreases-heat-increases-battery-life/

  5. DalSan M
    May 22, 2013 at 3:43 am

    Undervolting a processor means that the voltage going to the processor is reduced. If the voltage is reduced properly, then no performance loss would be made, but instead heat generation and battery life (if the device runs on batteries) would increase. If the voltage is reduced too much, then the processor would not be able to function properly and would through out errors and crash. I have undervolted my AMD C-60 netbook to the point that I was able to get 12 hours of battery life (depending on usage). As it is now since 1 1/2 years has passed, I get between 9 and 10 hours of battery life. I undervolt all of my phones so that I can gain a couple of hours of battery life. Since multi-core processors in computers have multiple running states, I underclock the processor as well to reduce heat generation and gain a little bit of battery life as well. (Underclocking is clocking down the processor to a lower, but stable and usable speed).

    Overclocking, usually done by changing the multiplier, is the process of increasing the speed of the processor to gain performance. This generally increases heat generation because of the increased wattage that must go into the processor for longer periods of time, and also decreases battery life because it takes more power to sustain the higher clock speed of the processor. Undervolting the overclocked processor helps reduce heat production as well as reduce the amount of electrical power going into the processor. Overclocking a processor too high, then the processor may throw errors and crash, or if the heat is not taken care of properly, can cause the processor to downclock to a lower speed to help reduce the heat generation while still being powered on. Too much heat for extended periods of time can burn out the processor and motherboard, so do be careful and make sure that proper ventilation is implemented, or reduce the speed of the processor to a stable and usable speed.

    • DalSan M
      May 22, 2013 at 3:50 am

      Sorry, the battery life would increase while the heat generation would decrease when undervolting a processor. When I underclock the processor, I underclock the lower states of the processor so that the maximum speed is lower, and this should not reduce performance because the higher processor state that allows the processor to get to the manufacturer stated processor speed would not be underclocked at all.

  6. ha14
    May 21, 2013 at 10:19 pm

    How Undervolting Decreases Heat & Increases Battery Life
    some cpus have power saving functions built in which undervolts (underclocking / undervolting ) the processor by default

    Undervolting and Overclocking on Ivy Bridge

    What Is Overclocking, And How It Can Help Your PC, Tablet, & Phone [MakeUseOf Explains]
    overclocking is for hardware running faster than the manufacturer tweakes recommendation, also if the hardware is not set for overclocking it can cause lots of troubles.

    • ha14
      May 23, 2013 at 3:44 pm

      Undervolting (CPU core voltage) is lowering the amount of power the processor draws at a certain frequency. This will not affect the performance since the clock speed of the processor is the same, but It decreases the power used, so you get better battery life. The only risk that you run in undervolting is an unstable system because you are in effect overclocking the CPU for that particular voltage. Some motherboard do not support setting a Vcore lower than the default top-speed Vcore in the BIOS,

      Underclocking is lowering the top speed of a processor, thus lowering the maximum speed of the processor will decrease the performance;

      so in order to good undervolt you have to underclock also! Before going to this exercise check the Vcore values of cpu with Intel if it is your processor.

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