Summary

• TJMax is the maximum safe temp for CPUs & GPUs set by manufacturers to prevent overheating.
• Check your CPU's TJMax using Core Temp for Intel or search on the manufacturer's website.
• Changing TJMax settings in BIOS can be dangerous; focus on lowering temps instead.

There is a lot of jargon when it comes to PCs. TJMax, which stands for Thermal Junction Maximum, is one example of this. However, knowing what it means is quite important and can be extremely beneficial to extending the longevity of your PC or laptop. It's never too late to teach yourself more about PCs, and once you know what they are, you'll likely remember them forever. While PCs may be designed to last for a few good years, the better we can take care of them, the longer they ultimately last.

What is TJMax?

Understanding the lingo

TJMax is a specification used mostly by CPU and GPU manufacturers to set the maximum safe temperature their CPU or GPU can run at before it starts to fail. It's essentially a fail-safe designed to make sure that if your CPU or GPU reaches a certain temperature, it dials back the voltage and performance to try to cool itself off to prevent it from overheating. In some cases, it may not work well enough, and if the CPU sees prolonged temperatures over its TJMax, it can trigger a complete PC shutdown to ensure it cools down.

There is no one universal temperature for figuring out a CPU TJMax. Instead, manufacturers like AMD and Intel will test their CPUs to determine the safest temperature for operation. This can vary by CPU model, so it is always worth checking. Intel seems to like to aim for around 100°C-110°C whereas AMD likes to have theirs a bit lower, at around 85°C-95°C.

How to check your CPUs TJMax

It's really quite easy

For Intel CPUs, you can download a program called Core Temp, and it will list your TJMax towards the bottom. Unfortunately, as you can see in the image above, it doesn't work on AMD CPUs such as my 7800X3D. It's also worth noting that some of the other PC monitoring software will include different TJMax values, such as distance to TJMax, which can be useful to some.

The best and easiest way, in my opinion, to find the TJMax is to search for your specific CPU and go to the manufacturer's website. If you search for 14900K on Google, one of the top results will bring you straight to that CPU's product page on the Intel website. There, you will find the TJMax and any info you need on the CPU, which could be even more beneficial.

Can I change the TJMax value myself?

Be careful when changing any settings in the BIOS

While not all motherboards allow this, some will let you go into the BIOS and change the TJMax value. I cannot stress enough how dangerous this can be, especially if you are trying to raise it. The manufacturers set these values for a reason, and unless you are 100% sure of what you are doing and why you are doing it, it is best to leave it alone.

The average user doesn't need to mess with the TJMax settings. If you are worried about your temps, you can set custom fan curves or lower your CPU voltage to help ensure it doesn't get too hot. There are a number of ways to reduce the heat in your PC without the need for hardware upgrades or messing with your TJMax settings.

Why does it all matter?

Excessive heat in your PC is not good, especially when it comes to the CPU. While CPUs are made to work under extreme pressure, it's best not to push them to their limits for prolonged periods. While your CPU TJMax might be 100°C, that doesn't mean you will want to run it at 99°C all the time. Doing this will not only affect your performance, but it will also have a lasting effect on your CPU and could even shorten its lifespan exponentially.