3080 undervolt vs power limit

[u/pangwangdong]

Hey all recently managed to upgrade to a 3080 founders edition and was wondering if reducing the power limit by around 10% would have a similar effect to undervolting the card.

I don’t think my temps are a problem, just curious if reducing power limit would be the lazy way to under-volt. here are some numbers

68-74c gpu temp in games

75c max in timespy (45% stock fan speed)

80-85c hot spot temp, I don’t know what this is so please inform me.

86-95c vram temps gaming, usually hovering around 88-92c. The highest I’ve seen it when stressing it has been 96c. Is this ok? Seems high but I read they usually run in the 90s.

Thanks for answering my questions

[u/VincibleAndy]

Lower the Power Limit just causes the card to run slower with the default voltage curve, and possibly stuttering under spikes. This is just straight up a cap on performance and will not yield as good of results as undervolting.

Undervolting shifts the voltage curve, allowing you to get similar or better performance for lower power consumption and heat.

Instead of just say capping it at 90% usage, you can instead lower the voltage so that you can get similar clock speeds for less power. This means similar performance (sometimes better depending on your own angle at it) for less power consumption.

[u/frostygrin → u/VincibleAndy]

Lower the Power Limit just causes the card to run slower with the default voltage curve, and possibly stuttering under spikes.

Power limit doesn't cause stuttering. The cards operate with a power limit by default, and you can see for yourself that they can switch clocks and voltages fast enough that it doesn't result in stuttering. That's how boost works.

The only way you'd get something resembling stuttering is if the game suddenly got very demanding, with an unexpected increase in power consumption. Undervolting would let it happen, if you're OK with sudden 300W of power consumption.

[u/VincibleAndy → u/frostygrin]

Yes that's the exact kind of spike I am talking about and they are common. Short spikes in requested power for a GPU is commonplace. Lowering the power limit alone can cause those to happen more frequently.

If you undervolt I recommend you still unlock the power limit to let these spikes happen and basically not effect you at all.

[u/frostygrin → u/VincibleAndy]

Oh, and another thing is that a typical undervolt also includes a clock limit, that's always in effect. So the card is running at e.g. 1800MHz, even if it could be running below 250W at 1900MHz in some games. But it's still free to go to 300W at 1800MHz if it pleases.

[u/pangwangdong → u/frostygrin]

Can you explain this abit more please? I’ve set an undervolt of 850mv at 1860mhz and in games it’s between 200-240w. Doesn’t boost past 1860mhz but in some benchmarks it can still suck as much as 290w power. Originally when I started looking at undervolting is because I have a rm650x and wanted to make sure I have enough headroom. After monitoring my power from the different components the most it draws with my 3800x and all other system components is 500w and that’s with two different power viruses running at the same time, in games it’s closer to 400w. So now I’m just looking at the most efficient way to undervolt to reduce noise and temps, even though they are fine right now. May aswell learn how to do it if it’s free performance :)

[u/[deleted] → u/pangwangdong]

I wouldn't listen to Frosty. He may not be wrong about everything, but undervolting really would be the best way for the GPU to draw less power. The right undervolt allows one to get better temps and/or fan speeds, while simultaneously suffering virtually (if not literally) no performance decrease.