Undervolt

[leartt]

hello  can u explain what is undervolt

[Hinjima]

7 minutes ago, leartt said:

hello  can u explain what is undervolt

Undervolting is reducing the voltage and power of a GPU or CPU to below factory settings to reduce power consumption or lower temperatures.

 

[leftvierdeadzwei]

It usually means to reduce the voltage offset of your GPU. This is done to lower temperatures and (sometimes) increase performance. 

 

Traditionally, people would overclock their GPUs and to get a higher overclock stable, you would often also need to manually increase the voltage to the GPU. For a couple of GPU generations now, the GPU driver does that mostly on its own, but often times, it gives the GPU more voltage than it actually needs. So people have moved to undervolting their GPUs, especially if they have small form factor builds where cooling isn't as good. A slight undervolt will usually yield the same performance while reducing temperatures, sometimes it can actually increase performance since it lowers temperatures and gives the GPU more thermal headroom to boost its frequency higher.

[WereCat]

Lowering voltage.

Allows higher clocks within the same power envelope. At the same clocks reduces power usage and temperature.

[starsmine]

To turn on a transister it needs x voltage to handle y current. 

Voltages do not just turn on in 0 time. its actually like charging a capacitor, which is V(t)=Vmax(1−e^(-t/RC))

The real voltage the transister sees is V(t), the input voltage is Vmax. V(t) only hits v(max) when time is infinite. time isnt infinint. 1 GHZ means the period is 1ns. to have a duty cycle of 50% we need the rising edge (or falling edge) to be less then 1/4 of that period (or way way less depending on the chain that its on so the results dont slip to the next clock which will corrupt data and hopefully cause a crash). 

Higher quality silicon has LESS capacitance (the C), so it can charge and discharge faster, meaning you can get away with lower Vmax at a given period and still turn on or off the transistors consistently. The default voltage profiles are so the poor quality bins still work at the advertised specs.

power of a chip is P = c f V^2 (power  = capacativeLoad * Frequency * voltage^2)

lowering the voltage has an exponential effect on power consumption, giving you more of your power budget to push frequency.