How do you lower your tension

Undervolting: lower the CPU temperature and fan speed using the core voltage

Friedrich Stiemer, Sebastian Schenzinger

Too high a temperature ensures that the CPU reduces its clock speed so as not to overheat. At the same time, the fans turn up and provide a higher background noise. This can be counteracted by undervolting the processor.

EnlargeLower the CPU temperature via the core voltage

If your CPU is throttled due to overheating, you can replace the processor cooler with a more effective model or switch to water cooling right away. If you don't want that, you can install additional case fans, which generate a constant flow of air inside the system and thus constantly provide cool air from the outside. However, these two options are not available, especially with notebooks. Here you can use another, more unusual method: reducing the core voltage of the CPU. This measure ensures lower power consumption and the associated lower temperatures. As a result, the processor can keep a higher clock rate longer and at the same time the fans don't have to turn up as much.

What is the difference between Core Voltage and VID?

The core voltage - also called VCore or Core Voltage - describes the supply voltage with which the mainboard supplies the processor for operation. The maximum core voltage is specified by the manufacturer and specified in the technical specifications as VID (Voltage Identification Definition). Each CPU model has an individual VID. However, not every processor really uses the specified voltage in order to work stably. For example, an AMD Ryzen 7 5800X needs a core voltage of 1.45 volts in order to achieve its boost clock of 4.8 GHz, whereas the other model also manages it with 1.4 volts. The reason: Even CPUs of the same type differ in details. Depending on the quality of the silicon, some chips require lower, some higher voltages in order to be able to keep a certain cycle. Manufacturers such as AMD and Intel therefore specify a VID with which the processor is guaranteed to run in order to ensure stable operation.

EnlargeUndervolting lowers the core voltage (VCore) of your processor. The result: You ensure a lower temperature and thus also save electricity.

The VCore itself, on the other hand, oscillates between different values. The clock frequency and load determine whether the core voltage is higher or lower. By default, the mainboard automatically adapts the VCore. The user does not notice anything and does not have to intervene. As a rule, however, the mainboard applies a significantly higher voltage than is absolutely necessary for a certain clock rate.

Change VCore in BIOS

If you want to change the VCore, you have two options: Either you go to the BIOS, or you use the Ryzen Master with an AMD processor or the Extreme Tuning Tool with an Intel CPU. The voltage of the processor can be read out in the BIOS and is usually specified with three decimal places in volts, for example "1.484 V". In order to get into the BIOS, you either have to press the key when starting up the PC F2 or Dist to press. Then switch to via in the BIOS F7 to Advanced Mode and open the OC menu. The names can vary depending on the motherboard manufacturer. If you scroll down you should come across the CPU's Core Voltage. In the default settings the entry is on "Auto". This indicates automatic management by the motherboard. If you want to change the core tension manually, you have to switch to the "Manual" or "Offset" option. Depending on the mainboard, a combination of both is also possible.

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This value has to be adjusted frequently, especially when overclocking. However, if you only want to increase the clock frequencies of your CPU to a comparatively small extent, you do not necessarily have to adjust the VCore. But if you want to get the maximum possible out of the chip in terms of clock speed, then you also have to get close to the core voltage. Instead of going to the maximum, you can also lower the VCore. This process is known as undervolting. Depending on the CPU in question, lower temperatures and lower power consumption can be achieved.

EnlargeThe voltage of the CPU can be dynamically adjusted with a voltage offset in the BIOS.

However, instead of setting a fixed maximum voltage, we recommend working with an offset. As already mentioned, the processor adopts different modes, the so-called C and P states, depending on the workload. An offset affects all of these states, whereas a fixed VCore value only defines the maximum voltage. We recommend that you reduce the voltage in the smallest possible steps, i.e. always by 10 millivolts. Save the changes in the BIOS, it is best to make a note of the value and then switch back to the operating system to test the computer. For example, you can play a complex game or run Prime95 for 60 to 90 minutes. If the computer does not crash, you can lower the voltage a little further. Repeat this process until the computer crashes or becomes unstable. Then boot back into the BIOS and increase the voltage to exactly the level at which the system was still running stably.

Note: A stress test is no guarantee of a 100 percent stable system. So if you wanted a completely reliable system, then undervolting is not recommended unless you know exactly what you are doing.

Undervolting via software

With a modern system, you no longer have to go into the BIOS to undervolt your processor. You can also use the in-house tools from AMD and Intel for this purpose. The process is ultimately identical. You can use a slider to set the core voltage or offset in the corresponding software. Here, too, you should feel your way in small 10 millivolt steps and repeatedly carry out stability tests until you have achieved the desired result. Unfortunately, however, not every CPU is compatible with the corresponding tools; at Intel, for example, you are limited to processors with the K or X suffix.

EnlargeWith Intel XTU, the voltage of the CPU can be easily adjusted under Windows.

Important: By undervolting the CPU, you lower the development of heat and can visibly reduce power consumption. Please note, however, that incorrectly set voltages can not only result in an unstable system, but also irreparable damage to the CPU. PC-WELT cannot accept any liability for any defects.

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