Even though I own a desktop computer, for reasons of convenience I am using my notebook more and more often, even at home. A few days ago, however, I noticed that the cooling fan is running very often – probably because of the higher temperatures during summer. This is especially annoying if one is watching 1080p or 4k videos or trying to concentrate on a task, like the editing of photos.
In order to convince the fan not to switch itself on every other minute, one has to reduce the voltage, which leads to lower power consumption and heat generation. A quick sear on the web showed that there two applications suitable for undervolting Intel’s current mobile processors: the XTU tool by Intel and “ThrottleStop”. Since the XTU tool needs too much performance according to a number of reports – which means that the processor is prevented from idling and that consumption therefore is even higher – I decided to give “ThrottleStop” a try.
As you can see on the second screenshot above, after comprehensive testing I was able to lower the voltage of my i5-4200U quite a bit. Power consumption and temperature fell by 2.5W (from ~20 to ~17.5W) and 5°C respectively under full load. The fan barely turns on now during everyday usage. Even during batch processing in SPP it does not switch to the highest setting immediately, like it did before. It does switch on, but only at the lowest speed, and therefore stays pleasantly silent. 🙂
However, you should be careful if you are planning to tame an annoying fan and to increase battery life a little. Immediately reducing voltage by 100mV is not a good idea. It is better to lower it in increments of 5mV and to test the notebook’s stability thoroughly afterwards. Benchmark applications like prime95, which really make the CPU sweat, do a good job. In addition, the notebook should be used normally for some time to make sure that it stays stable even when the CPU is not running at full capacity and when idling. This may seem illogical at first, but it makes sense if we keep in mind that low-power processors automatically adapt clock cycles and voltage to the load, but that in “ThrottleStop” it is only possible to set one so-called “offset” value which reduces the voltage in every power state by the same absolute value. Because of this it is completely possible for a device to be stable with a high CPU load, but to freeze immediately as soon as the processor hasn’t got anything to do and reduces its clock. If the lower voltage does not agree with the CPU and the notebook freezes as a consequence, you should perform a restart and increase the voltage again by 10 to 15 mV.
It should also be mentioned that undervolting, as well as overclocking, can damage the hardware. If you’re reducing the voltage, you are doing this at your own peril. I am not assuming any liability for any damage.