The more strenuous the tasks you carry out on your PC, the more your CPU (processor) will heat up. This becomes particularly noticeable during gaming or heavyweight video-editing, but your CPU may be prone to overheating anyway if it’s poorly ventilated or the thermal paste on the CPU has worn out. Luckily, there’s a borderline-miraculous tool that can reduce high temperatures and reduce power usage by a process called “undervolting.”
It’s called Throttlestop, and this article shows you how to use it to undervolt your CPU.
Note: if you’re unsure about whether your CPU temperatures are too hot, read our guide on how to monitor your PC temperature in Windows 10. Certain laptops are also locked off from undervolting, which you can check by looking for a “Locked” sign in the Throttlestop FIVR menu.
What Is Undervolting?
Before pushing on, it’s worth knowing what undervolting is, as it’s a pretty serious process. While undervolting doesn’t damage your CPU, overdoing it can make your system unstable (though it’s easy to reverse). Overvolting, on the other hand, can damage your CPU if abused, but used carefully, can allow you to overclock your CPU to higher speeds. (We won’t be covering that today.)
Undervolting, simply put, reduces the amount of power/voltage being directed to your CPU. The more power sent, the hotter it gets. The less power, the cooler it gets. Simple. Another perk of undervolting for laptop users is that it extends battery life.
Best of all, undervolting your CPU doesn’t noticeably affect performance, even during high-intensity activities like gaming. It really is as good as it sounds!
Throttlestop is a tool with many purposes. Its very name refers to its use in overriding throttling systems in your CPU to increase performance, but we kind of do the opposite here.
First, download and install Throttlestop, then open it.
Let’s take a look at the checkboxes on the main Throttlestop screen.
We’re only going through the ones that are relevant to modern CPUs, as several of those boxes relate to features for much older PCs. The following are the features you should look for:
Disable Turbo: this setting will ensure that none of the cores on your CPU run faster than their base clock speed. If you have a base clock speed of 2.6GHz that’s capable of Turboing up to 3GHz, checking this box will make sure it stays in the 2.6GHz region instead of boosting.
BD Prochot: a safety feature that seriously throttles your CPU when things get too hot inside your laptop. Generally, throttling will kick in when your CPU reaches 100C, but with this box ticked, the CPU will throttle even when your GPU gets too toasty. It’s a handy safety measure that’s worth having on for those rare extreme cases.
Speed Shift: on more recent CPUs (2016 onward), Intel released this feature, which helps the CPU respond faster to changes in the software-set clock speed. If this option appears in Throttlestop for you, then you should switch it on.
SpeedStep: if your CPU is older than the Intel Skylake generation (2015), then Speedstep does the same job as Speed Shift. By all means, switch this on if you have an older CPU.
C1E: switching this on will help save power when you’re running low on battery, as Throttlestop will switch off your cores automatically based on how much strain they’re under. You don’t need to have this on when plugged into the mains.
Undervolt Your CPU Using Throttlestop
Next up is the four select-circles at the top left. These let you switch between different profiles, each of which can have its own undervolt settings. We’ll switch this to “Game,” as we’re creating a profile for gaming, but you can leave it on “Performance” if you like.
So with the profile you want to set up selected, click the “FIVR” button in Throttlestop. In the new window, tick the “Unlock Adjustable Voltage” box.
Next, we decrease the “Offset Voltage” slider, which is the undervolting part. We recommend decreasing this to “-100mV” to start.
Once you’ve done that, click “CPU Cache” in the “FIVR Control” section and set it to the same voltage. It’s crucial that CPU Core and CPU Cache always have the same Voltage Offset.
Once you’ve done this, click “Apply” and continue to track your system stability and CPU temperatures. (You can track CPU temperatures from the main Throttlestop window.)
If your system remains stable (no blue-screen crashes), then you can continue decreasing the CPU Cache and CPU Core voltage in -10mV increments to further reduce your CPU temperature. If you reach a point where your system crashes, reboot your PC, open Throttlestop, and bring the Offset Voltage back up towards a point at which your system was stable.
Different CPUs can handle different levels of undervoltage, so you’ll need to experiment a bit to find out the limits for your CPU. My Intel i7-6700HQ CPU goes down to -150mV with no problem, but yours may differ.
When you’re done making adjustments, click “OK” in the FIVR control Panel, then “Turn On” in the main Throttlestop window.
If you want to avoid having to open Throttlestop manually each time you want to undervolt, you can set it to open on Windows startup. Refer to our guide on how to use the Windows Task Scheduler for more info.
Using this method, I reduced my CPU gaming temperature from nearly 90°C down to a much less alarming 70ºC to 75°C. This is just about as much effect as you can have on your CPU temperature from within Windows.