I'm mainly posting this for people who don't have much experience with undervolting. I assume most people here already have their GPUs undervolted, but I thought this might be useful in case someone comes across this thread in the future.

For context, I'm using an RTX 4090.

I've seen a lot of people saying that DLSS 5 uses a lot of power and can potentially cause the 12VHPWR cable on our GPUs to melt (which is true), but undervolting can actually allow you to use DLSS 5 while keeping power consumption roughly the same as running without DLSS 5 and without an undervolt.

In these two screenshots (both using MFG x4, one without DLSS 5 and the other with DLSS 5), we're at around 390 W in both cases.

I also took a few screenshots if anyone is interested:

DLSS 5 OFF / ON
MFG OFF / ON (x4)
RTX 4090 with and without undervolting

# 1. DLSS 5 OFF (MFG x4)

Without undervolting:

With undervolting:

# 2. DLSS 5 ON (MFG x4)

Without undervolting:

With undervolting:

# 3. DLSS 5 ON (MFG OFF)

Without undervolting:

With undervolting:

So, in terms of performance, the results are very similar, while undervolting gives you an average power reduction of around 50 W. You can see the power consumption in the top-right corner under the GPU section.

This means that even with DLSS 5 enabled, you can stay below the 400 W mark. Without undervolting, DLSS 5 pushes power consumption to around 435 W.

Here are my MSI Afterburner settings if anyone is interested. I've been running these settings since 2022, and they've been extremely stable. I've never had any issues with them. Hopefully this isn't too messy. I did my best to make it as clear as possible

Good data. I've been running a similar curve on my 4090 since launch and it's wild how much headroom these cards have. That 50W drop for basically the same frametime is the whole reason to do it. The cable melting fear gets people's attention but the real win is just a quieter, cooler card that's not pissing away electricity for no gain.

What’s the difference between this and limiting the total power consumption in the Afterburner or Nvidia app?

Undervolt makes it more efficient..power limit just strictly makes it slower

Limiting power does exactly that. You're effectively just capping how fast the card can run based on power.

Undervolting tells the GPU to run at a faster clock speed while also using less power. You're effectively "shifting" the curve, not capping it.

noob question but how is the gpu able to just run faster with less power put into it and nothing else changed?

Undervolt does not mean lower power at full load. I’ve got my 5080 running at 945mv but at 3000mhz with power limit at 110% and it was still drawing 400w. And stock that card can draw +1v at full load

I just got a new 5070 and didn't know this undervolt thing. I will definitely try it. Thank you

Overhead. GPUs aren’t individually factory configured for maximum performance and efficiency.

GPU stability is a product of clock speed and voltage. Meaning, a GPU needs a certain voltage to run at a certain clock speed.

Every GPU ships from the factory with some amount of overhead so that the user doesn't experience crashing. Meaning, every stock GPU is running more voltage than it technically needs for the sake of stability. Each card is a little bit different too, but the manufacture finds a curve that works for all cards.

The process of undervolting involves testing how much stability overhead your individual card has, and eliminating as much of it as you can while still maintaining stability.

It's just silicon lottery

Imagine a car manufacturer and the amount of oil that goes into a car, most of the time it's more then is needed. But some cars are of higher rate that could do with less.

GPUs are limited by heat and Power if they detect that one of those things are at the ceiling it will throttle. Undervolting raises those ceilings

You should consider doing it even when you don't use DLSS 5. It does wonders especially on Blackwell GPUs, because they overclock like crazy. In my case (with RTX 5070) going from stock 1.050mV to 900mV helped immensely - coil whine is basically non-existent, temps barely go over 60c and fan is inaudible.

It is engine dependent.

Some engines will pull a lot more power out of your 945mv.

Try comparing default and undervolted on an engine that doesn't run like a virus.

If you're comparing with NR on... Well NR runs like a virus. It lowers your core clocks because it needs more power.