How to monitor CPU usage

Various ways to monitor CPU usage

What is your CPU usage? It's a simple question, but a complicated answer. The CPU is the brains of the operation when it comes to a computer. Unlike with the human brain, we can get an exact measure of how much processing capacity is in use at any given time. Whether one is a heavy multitasker or trying to optimize performance in a video game, monitoring CPU usage is essential to ensure getting the most out of the processor and identify any performance issues.

In this how-to guide, we'll show you various ways to monitor CPU usage, from quick and simple methods to more detailed approaches. We'll also cover how to check CPU temperature, important for those who overclock or are concerned about overheating.

What is CPU usage?

CPU usage is typically reported as a single percentage, indicating the current utilization of the CPU's resources. For example, if the usage is at 100%, the entire CPU is busy, while 25% usage means only a quarter of the CPU is occupied. However, modern CPUs consist of multiple cores, which adds complexity to CPU usage measurement.

Consider a quad-core CPU, where one core is maxed out while the rest are idle. In such cases, the overall CPU usage may be reported as 25%, but the performance is limited to the maximum capability of that core. This limitation is often observed in video games that don't effectively utilize multiple CPU cores, resulting in the frame rate being limited by the performance of a single core or thread.

In such scenarios, a single CPU percentage is not very informative. That's why we'll explore methods that allow you to monitor each individual CPU core's performance, helping you identify any bottlenecks.

Windows CPU usage

Windows provides robust and detailed performance monitoring tools, with each version of the operating system offering more detailed information. Here's how to access these tools in Windows 11 (also applicable to Windows 10):

1. Launch Task Manager by pressing Ctrl + Shift + Escape.
2. Open the Performance tab and click on "CPU." This displays a graph showing the percentage of total CPU power in use.
3. (Optionally) Right-click on the graph and select "Change Graph to > Logical Processors." This view shows the utilization of each individual CPU thread, which may not correspond to the number of physical CPU cores due to some cores handling multiple threads simultaneously.

Using the Windows Task Manager is effective when monitoring CPU usage in windowed applications. However, if you're using a full-screen application like a video game and don't have a multi-monitor setup, Task Manager won't provide the desired information.

Fortunately, Windows includes the Xbox Game Bar feature, allowing you to pin a performance monitoring widget on top of a full-screen app. Here's how to use it:

1. Launch Xbox Game Bar by pressing Win + G.
2. (Optionally) Move the performance widget to a non-obtrusive spot on the screen using your mouse.
3. Pin the Performance Widget with the Pin button. Clicking on the pin button ensures the performance widget remains visible even after closing the Game Bar.
4. Close the Game Bar with Win + G. Once the widget is pinned, you can close the Game Bar, and the performance information will remain overlaid on the full-screen app.

While the Xbox Game Bar offers a basic CPU usage meter for games and full-screen applications, it doesn't provide details about per-thread CPU usage. For a comprehensive view of CPU activity while running a full-screen 3D application, the MSI Afterburner combined with Riva Tuner Statistics Server (RTSS) is recommended. Here's how to set it up:

1. Download and install MSI Afterburner.
2. Head to the