You'll find countless complicated articles and guides with advice and instructions on undervolting your Ryzen processor, but is it possible to reap the rewards without putting in the effort? The answer can be a positive "yup!" if you don't mind some instability during the first weeks of using your new PC.

Let's see the quickest, easiest, and safest way to do precisely that to undervolt your new CPU and avoid wasting days of your life testing if everything works as it should.

Before We Begin...

Properly overclocking or undervolting a CPU requires a lot of trial and error. In the process, some crashes are inevitable. However, in this article, we'll see how you can "sidestep" most of the testing. To achieve this:

  • We'll begin with too aggressive values to intentionally crash the PC.
  • We'll then "dial down" those settings to find "relatively safe" and almost crash-less values.

With this approach, we'll follow the opposite route than usual when undervolting: instead of spending days (or even weeks) stress testing the PC to find the optimal values for its CPU, we'll accept some daily instability to cut down on the initial stress-testing time.

Since with this approach, you will face more random crashes than usual, remember to save your work (or game progress) more frequently. Also, keep a full OS backup handy, just in case.

Note that the process we'll see should be safe for your hardware since:

  • Undervolting reduces instead of increasing the electric current "flowing into" the CPU. Thus, it's impossible to "fry it".
  • AMD includes safeguards into its Ryzen family of CPUs that continuously monitor their state. If some potentially dangerous values reach their limits, your PC should automatically power off.

Still, AMD advises you don't try overclocking or undervolting since they can void your CPU's warranty. Thus, we should follow suit. Proceed at your own peril.

What Is Undervolting?

We already have many articles on undervolting, which you can check if, for example, you want to undervolt your laptop with Intel XTU or undervolt your graphics card to have it run quieter and last longer.

We've also covered many of the best overclocking apps to boost PC performance, which you can use for the opposite process, overclocking.

Before proceeding, we suggest you check all those articles to learn more about both processes since they're opposite sides of the same coin.

The short version is that undervolting is the opposite of overclocking. By reducing the amount of electricity "going in" a component, you can decrease its temperature.

Theoretically, this also leads to a drop in performance. Practically, that's not the case with AMD's new CPUs, thanks to a feature known as Precision Boost Overdrive, or PBO for short.

What Is PBO?

Precision Boost Overdrive, or PBO for short, is a new feature in modern AMD CPUs (from Ryzen's 2nd family). Unlike typical overclocking, it doesn't lead to a higher CPU frequency. And also, unlike "classic" undervolting, it doesn't lead to a drop in performance.

Instead, PBO takes advantage of the CPU's self-monitoring features to allow you to reduce the electricity that "flows through it", leading to lower temperatures, but without lowering its operating frequency. Quite the opposite, the better thermals allow the CPU to avoid throttling and, as a result, keep all its cores working at a higher frequency for longer.

What Is CoreCycler?

CoreCycler is a PowerShell script that can help you test modern multicore CPUs by "cycling" between them and individually stress-testing each core. Doing that lets you easily pinpoint which core is unstable with your current hardware settings.

Since in this article, we'll be using it for our testing, download the script from CoreCycler's official page at Github. Then, extract the archive on your desktop for easy access before we proceed to the actual undervolting and testing.

Make Your Computer Crash, Then Backtrack

With all theory out of the way, let's jump into action... and make the PC intentionally crash. Note that the settings we'll see are in a different spot for each motherboard's UEFI menu. Also, the number of cores (and, thus, PBO values) depends on your CPU.

For this article, we'll use an ASUS TUF Gaming motherboard with an AMD Ryzen 5900x CPU. The menu options we'll refer to are for that motherboard's UEFI menu.

We also assume you're using your motherboard UEFI's default values. If you've tweaked them, refer to your motherboard's manual to return them to their defaults, and set any option related to overclocking to "disabled".

  • Restart your PC and press the Del key repeatedly to enter its UEFI menu. When there, press F7 to switch from its "simple" to the "advanced" menu, which exposes all available options.
  • Move to the Ai Tweaker page and ensure all voltage-related options are set to default values. If your motherboard UEFI has applied any "optimized values", like increased DRAM Voltage, change those settings to Disabled or Auto. Alternatively, enter manually the default values for your hardware. For example, our system's DDR4 RAM sticks run at a typical 1.350V.
  • Ignore any mention of PBO on the Ai Tweaker page. Instead, move to the Advanced page. There, scroll down to find and select AMD Overclocking.
  • Accept the warning that any further tweaks might damage your processor. We stress that although what we'll see shouldn't lead to any problems, it's your choice if you decide to proceed. There are always some inherent risks when "fooling around" with hardware settings.
  • Choose Precision Boost Overdrive.
  • Change the setting of the Precision Boost Overdrive drop-down menu to Advanced.
  • Change the PBO Limits to Manual.
  • Enter your CPU's default PPT, TDC, and EDC values in the following fields. For a 105W AMD CPU, like the Ryzen 5900x we're using, PPT is 142W, TDC is 95A, and EDC is 140A. For 65W AMD CPUs, like the Ryzen 5600, PPT is 88W, TDC is 60A, and EDC is 90A.
  • Leave Precision Boost Overdrive Scalar to Auto. Alternatively, you can change it to Manual and set it to 1x.
  • Make sure CPU Boost Clock Override is set to Disabled.
  • Enter the Curve Optimizer submenu. Change the Curve Optimizer setting to Per Core. Then, set all cores' Curve Optimizer Sign to Negative and all Curve Optimizer Magnitude to 30.
  • Move to UEFI's last menu, Exit, and choose Save Changes & Reset.

    • If your PC crashes during the next reboot, enter its UEFI again, move to the Curve Optimizer submenu, and reduce all Curve Optimizer Magnitude values by two (from 30 to 28). Rinse and repeat until you can enter Windows as usual.

    If your PC "locks" completely, refer to your motherboard's manual for instructions on resetting its UEFI to the default settings. Usually, you can do that by pressing a semi-hidden button on the motherboard, "shorting" two pins with a jumper for five seconds, or, in worst-case scenarios, removing the motherboard's CMOS battery for one or two minutes.

    CoreCycler Testing

    Enter the folder where you've extracted the CoreCycler archive's content. Right-click on config.ini and edit it with your favorite text editor (Windows Notepad will do).

    Find and change the following values if yours are different.

    Under [General]:

  • stressTestProgram = PRIME95
  • runtimePerCore = Auto.
  • suspendPeriodically = 1
  • coreTestOrder = Default
  • skipCoreOnError = 1
  • stopOnError = 0
  • numberOfThreads = 1
  • maxIterations = 10000
  • coresToIgnore =
  • restartTestProgramForEachCore = 0
  • delayBetweenCores = 15
  • disableCpuUtilizationCheck = 0

    • Under [Prime95]:

  • mode = SSE
  • FFTSize = All

    • Under # Custom settings for Prime95 - [Custom]:

  • MinTortureFFT = 4
  • MaxTortureFFT = 8192
  • TortureMem = 0
  • TortureTime = 1

    • Save your tweaks and close the file. Then, double-click on Run CoreCycler.bat to start stress-testing your CPU.

    If, after around twelve hours, your PC's still going, you're more or less OK. However, it's more probable your PC will crash and reboot.

    If that happens, when back on your Windows desktop, revisit CoreCycler's folder. Enter the logs sub-folder, and open the latest log. Look for the last Set to Core entry - in our case, it was "Set to Core 11 (CPU 22)". Note that number.

    Each physical core on a multicore CPU appears as two cores in the OS and most UEFI setups. Core 1 appears as Cores 1+2; Core 2 is Cores 3+4, etc. However, to complicate things further, the core count usually starts at 0. The following example list for a hypothetical 4-core CPU might help you make sense of the numbering:

    • Core 0 = Cores 0 + 1
    • Core 1 = Cores 2 + 3
    • Core 2 = Cores 4 + 5
    • Core 3 = Cores 6 + 7

    With that in mind, return to your UEFI's Curve Optimizer submenu. Locate the core that caused the crash according to CoreCycler's log and reduce its Core Optimizer Magnitude value by two. So, if you had the value set to 30, dial it down to 28, if it was 28, reduce it to 26, and so on.

    Move to the Exit menu again, Save your changes, and repeat all steps above until your PC stops crashing during testing with CoreCycler.

    Is My PC Now Free of Blue Screens?

    Even if your PC stopped crashing during testing with CoreCycler, that doesn't mean it's 100% stable. You'll still meet the occasional crash. You can only be sure of its stability if you've been using it for weeks or even months without a single crash.

    Thus, even after your PC stops crashing while testing it with CoreCycler, don't take its stability for granted. Keep saving frequently, and have a full OS backup handy. You never know if and when your PC will crash again.

    Getting CoreCycler Up and Running on Windows

    With the above method, you'll have completed most stress-testing in a single day and have a cooler, undervolted, and better-performing PC in a fraction of the time you'd need for proper extensive testing.

    You might be exchanging some day-to-day stability to reduce testing time, but isn't that better than waiting for your brand-new PC to stop being useless until it completes a week or more of stress tests?

    ncG1vNJzZmivp6x7rq3KnqysnZ%2Bbe6S7zGisp5yVp8OwuNNmqbKylaN6pLzUrGScsZOhsrN7