Undervolting in the PC world means to reduce the voltage input into a part such as a CPU or GPU from the amount the motherboard would usually deliver. This can reduce heat, noise from the cooling solution and in some cases increase performance/overclocking potential
The first idea to undervolting is to reduce heat output. Power is measured and wattage and that is a combination of amps * voltage. So let us take a Ryzen 5 3600 and under PBO (Precision Boost Overdrive), it is producing 95W of power. At 1.35V and a current of 70A, that would yield about 95W. If you can undervolt to say 1.2V, that will lower your output to 84W which is easier to cool and thus gives more thermal headroom for higher clocks. However, each piece of silicon requires different amounts of voltage to maintain certain frequencies and it can vary from each physical chip even if it's the same model.
Another reason why people undervolt is to lower the need for loud cooling solutions. Noctua for example includes something called LNA or Low Noise Adapters which will automatically reduce the maximum speed. The same can be used in conjunction with undervolting a CPU or GPU. If you're using less electricity you will have to dissipate less heat, and the fans can run at an even lower RPM. This will reduce noise from your cooling solution.
Lastly, performance can be a factor in 2 different ways. Undervolting to a fix voltage will reduce maximum heat output and also prevent spikes above the maximum fixed voltage. Voltage spikes can causes issues with smooth & consistent performance as this often causes spikes in temperature that can take several seconds to fix, even longer.
As eluded to above, if thermals is limiting performance and overclocking potential, undervolting can help increase performance. As seen in the video above, undervolting saw a 4-5*C drop in temperatures while increasing performance by 3-4%. This is even a bigger deal when you're saying dealing with a reference RX 5700 where it can hit 110*C in some places which causes speeds to reduce due to throttling.
Undervolting is relatively safe to do, especially on AMD cards. I will explain the process of how I did it, but depending on the card, the process might be different. The stock settings are 1750MHz Core, 875MHz Memory and around 1006-1018 mV for the voltage.
Inside of Radeon settings, there is a program called Wattman. With the current RX 5700/5700 xt cards, there are features to automatically OC the Core Clock, Memory Clock or undervolt. You can only do one at a time. I tested each with Super Position to see if they were stable. So I combined all 3 settings and tried to test it:
Sapphire:
ASrock:
And they crashed. I slowly increased the mV by 15 until it was stable, remembering where the stock voltage started at. Increasing the voltage too high can kill a card, so I would be very careful exceeding the stock voltage and this defeats the purpose of undervolting.
From here, I was able to dial in each setting for each card:
Sapphire:
ASrock:
In the video above, you can see how the performance went up and the thermals went down. Increasing the voltage to stock did not increase performance. But AMD does limit how much you can do and is pretty safe as long as you're careful with voltages.
The first idea to undervolting is to reduce heat output. Power is measured and wattage and that is a combination of amps * voltage. So let us take a Ryzen 5 3600 and under PBO (Precision Boost Overdrive), it is producing 95W of power. At 1.35V and a current of 70A, that would yield about 95W. If you can undervolt to say 1.2V, that will lower your output to 84W which is easier to cool and thus gives more thermal headroom for higher clocks. However, each piece of silicon requires different amounts of voltage to maintain certain frequencies and it can vary from each physical chip even if it's the same model.
Another reason why people undervolt is to lower the need for loud cooling solutions. Noctua for example includes something called LNA or Low Noise Adapters which will automatically reduce the maximum speed. The same can be used in conjunction with undervolting a CPU or GPU. If you're using less electricity you will have to dissipate less heat, and the fans can run at an even lower RPM. This will reduce noise from your cooling solution.
Lastly, performance can be a factor in 2 different ways. Undervolting to a fix voltage will reduce maximum heat output and also prevent spikes above the maximum fixed voltage. Voltage spikes can causes issues with smooth & consistent performance as this often causes spikes in temperature that can take several seconds to fix, even longer.
As eluded to above, if thermals is limiting performance and overclocking potential, undervolting can help increase performance. As seen in the video above, undervolting saw a 4-5*C drop in temperatures while increasing performance by 3-4%. This is even a bigger deal when you're saying dealing with a reference RX 5700 where it can hit 110*C in some places which causes speeds to reduce due to throttling.
Undervolting is relatively safe to do, especially on AMD cards. I will explain the process of how I did it, but depending on the card, the process might be different. The stock settings are 1750MHz Core, 875MHz Memory and around 1006-1018 mV for the voltage.
Inside of Radeon settings, there is a program called Wattman. With the current RX 5700/5700 xt cards, there are features to automatically OC the Core Clock, Memory Clock or undervolt. You can only do one at a time. I tested each with Super Position to see if they were stable. So I combined all 3 settings and tried to test it:
Sapphire:
- 1830MHz Core Clock
- 930MHz Memory Clock
- 970 mV
ASrock:
- 1830 Core Clock
- 930MHz Memory Clock
- 956 mV
And they crashed. I slowly increased the mV by 15 until it was stable, remembering where the stock voltage started at. Increasing the voltage too high can kill a card, so I would be very careful exceeding the stock voltage and this defeats the purpose of undervolting.
From here, I was able to dial in each setting for each card:
Sapphire:
- 1850MHz Core Clock
- 1816MHz Actual
- 915MHz Memory Clock
- 984 mV
- 987 mV Actual
ASrock:
- 1850 Core Clock
- 1804MHz Actual
- 930MHz Memory Clock
- 970 mV
- 976 mV Actual
In the video above, you can see how the performance went up and the thermals went down. Increasing the voltage to stock did not increase performance. But AMD does limit how much you can do and is pretty safe as long as you're careful with voltages.