For years us PC nerds have loved overclocking graphics cards in order to maximize performance.
But these days the graphics card makers seem to have squeezed out all that extra performance
themselves, thanks to the turbo and boosting algorithms.
So, what can you do now to squeeze more out of your gear?
Well, how about making it more efficient?
In this video I want to tell you about undervolting and show you how you can do it to your own
GPU.
Let’s get started.
Overclocking a graphics card is so several generations ago, the new name of the game
is efficiency.
Undervolting allows the graphics card to run more efficiently and pushes it’s capabilities
in order to target one of two different goals.
You can either simply keep the performance about the same while using even less power
which allows it to run cooler.
Or you can find additional clock rate headroom for your GPU core now that you’ve reduced
the power requirement to hit those stock clocks.
Doing this is fairly easy with the ability to lower the voltage frequency targets built
into programs like MSI Afterburner, EVGA Precision X, or Wattman in the Radeon Settings software.
For this video I’m going to show how to do this using what has, according to the Steam
hardware survey, turned into one of the fastest adopted modern GPUs: the GeForce RTX 3070.
I’ll be using a Founders Edition version on my test bench that features a Ryzen 7 5800X,
32GB of DDR4 3600, and a PCIe Gen 4.0 NVMe SSD,
But you can overclock your graphics card on almost any modern system so none of those
details are terribly relevant other than you knowing what system I’m using.
That’s because we’re focused much more on the results using the PCAT system to monitor
power and performance.
PCAT is the Power Capture Analysis Tool that Nvidia released some time ago that allows
me to isolate the graphics card power draw from the entire system.
It also allows me to capture PCIe connector power as well so I have an actually accurate
picture of the power the GPU is pulling under use and even while idle.
With this setup I’ll be trying out both goals.
One test for maximum efficiency, meaning maintaining performance while reducing power, thermals,
and noise.
And the other test for a traditional overclock to see how the old school way of doing things
goes.
The process of undervolting is rather easy.
For this example I’m using my preferred software, MSI Afterburner, and this is how
I do it.
Once Afterburner opens, I hit control F to bring up the voltage/frequency curve editor
to see what changes are taking place.
Bringing up the specs of this particular GPU, I can see that it’s reference boost clock
is 1730MHz, so I want to drop the voltage curve in order to pull back to reference.
So then going to the Core Clock slider I pull the clock rate down about 290-300MHz, which
drops the entire voltage curve with it but ultimately reduces the top end boosting speed
so that I can now control it.
The amount to drop will change depending on which GPU you have, so be sure to check the
product page or use a program like GPUz in order to find that reference boost.
Now that I’ve leveled things off to stock I want to control when and how far it boosts
myself.
To do that I move back over to the Voltage/Frequency Curve Editor and pick a plot point on the
curve, typically between 850mV and 950mV.
This is mostly an arbitrary number but I’ve not found a single GPU that wouldn’t hit
the rated clock boost at 950mV, so that should be a good starting point.
So I’ll click on 950mV and raise the frequency dot on that voltage up to around the stock
operating frequency, which in this case is just over 1900MHz.
I recommend using the arrow up key to do this as dragging with the mouse pointer is wildly
inaccurate.
When you do this you’re telling the GPU to target a specific voltage at the given
frequency rather than letting it continue on past that point.
Now you’ll typically be locked into that frequency under load if you’ve hit the sweet
spot and won’t see the Core Clock jump all around.
Next is to determine whether the GPU is stable with these settings, meaning your games won’t
lock up or crash to the desktop.
I recommend using some of the most stressful games you own in order to test against because
if it's stable there then there is a good chance it’ll be stable in every other game.
Even better, use games that have built in benchmarks as this also allows you to track
your changes in real time.
Once things seem stable you have the option of going lower on the voltage for the same
clocks, or increasing the clock rate to find your sweet spot.
If you’re wondering how aggressive you should move on the voltages you test, I recommend
moving in 25mV increments until you find a crash, then go back to the last stable setting.
So essentially you can target better performance at lower power draw and heat output, or you
can sacrifice a little bit of performance and see just how low you can go on power and
thermals.
After each setting change it's good to go back to the same benchmarks and run them again
to make sure things are stable and to see how your settings have affected performance
and thermals.
You need a bit of patience while doing this dance of setting changes and testing stability,
but it can quickly become a fun game in itself!
And don’t worry, with undervolting there is no risk of pushing things too far and breaking
since essentially you’ll just crash from NOT having enough power to run the GPU rather
than overdoing, kinda like starving an engine of fuel.
In order to highlight the results of my own testing I used Assassin’s Creed Valhalla
as an example, which was tested using the built-in benchmark at 1080p Very High settings.
The stock core clock on my RTX 3070 is 1965MHz, which is quite respectable.
First I used MSI Afterburner to do a traditional overclock and push the Power Limit to +100,
the Core clock to +80, and the memory to +1000.
This overclock resulted in a core clock of 2048MHz on the core.
Then I used Afterburner to undervolt, and this was a fun one.
I set the core clock to hit 1920MHz but at 925mV, stock was 1965MHz at 1125mV, but I
pushed the memory by +1000 offset.
This basically resulted in a locked 1920MHz through the duration of my testing.
But how did that fare in performance?
Well, the combination of the core undervolt and the memory overclock resulted in the performance
being within the margin of error, a very solid result.
The overclocked performance gave us a bit of a boost in performance as expected, but
at what cost?
See that’s the interesting part here with these power-hungry big boys.
Sure we got more performance when overclocked but the power draw of the three configurations
is wild when you’re able to truly isolate the GPU and see what’s going on.
The stock settings result in an average of just over 180 watts of power consumption with
the overclocked settings, which shows it being power limited by the card.
If you have a beefed-up version of the RTX 3070 then you could likely push this even
higher.
BUT the money is on the undervolt here, aiming for the same performance as the stock settings
but with a 44-watt reduction.
In percentages, we’re looking at a 24% decrease in power consumption.
Not only does this result in lower power consumption but also an easier to cool GPU, because you’re
now working with cooling even less wattage.
Now for the Founders Edition, it didn’t move the needle terribly in thermals as we
went from 64*C down to 61*C. But that’s with the stock fan curve, meaning it didn’t
have to spool up as much and was audibly quieter.
All around, undervolting seems like a winning move.
So if it’s such a win why isn’t it just the way things are?
Well, it’s because neither I, nor the GPU manufacturers, can guarantee you will have
the same results.
It’s like with overclocking, there’s a silicon lottery that comes with it.
And, just like with overclocking, anything that modifies the stock values can introduce
instability.
What works today might not work after the next driver update.
Thanks to the BIOS locks on modern graphics cards you’ll HAVE to run 3rd party software
to do this and hope for the best.
The exception is Radeon cards where you can use the Radeon Software but the point still
stands.
It’s a software solution, not a permanent hardware shift.
And once again, if it’s stable in one game that doesn’t mean it’s going to be stable
in every game, so I personally recommend trying it with your most intense games.
I mean, we all know a game like Forza Horizon 5 is much easier to run than a game like Hitman
3, so test with the tougher game because you don’t want to dial your GPU in on Forza
then crash the moment you open up Hitman 3 do you?
So should you do it?
Honestly, if you’re comfortable tinkering within software and don’t mind frequent
restarting until you dial in that perfect voltage and frequency combination..
then yeah, I think most people should be willing to give this a try.
It’s a software modification anyway so it’s easy to undo and you’re going down in voltage
required, so burning up stuff is basically out of the question.
What you have to gain from it is a quieter, cooler, and more efficient running graphics
card.
As I leave you I want to know have you done this?
Will you do this?
Or do you just do like most and let things roll by default and let your graphics card
do its thing!
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