If you want to know how your Apple computer's CPU and GPU (Graphics Card) performance, you can check that via Activity Monitor.
However, you can see in real time how your CPU and GPU are performing through the Activity Monitor panels in Mac OS.
These are panels that you can place above all other windows to monitor how your CPU and video card hardware is performing. Think of it as real-time statistics about built-in hardware.
Enable hidden activity view panels (Mac)
To get started, you need to open Activity Monitor. In the Applications folder, go to Utilities and open Activity Monitor.
You can also press Command ⌘ + Spacebar and enter Activity Monitor in Spotlight.
In the Activity Monitor menu in the top bar of Mac OS go to Window and activate one or all three panels. CPU usage, CPU history and/or GPU history. You can also press ⌘ + 2, ⌘ + 3, or ⌘ + 4 on your keyboard if you prefer.
Three panels will now appear, each with a real-time meter displaying CPU performance per core, CPU history and GPU (graphics card) performance.
CPU panel
Each meter lights up depending on how much CPU activity is happening in that specific core. For example, if five segments are lit, you are using 50 percent of the CPU capacity of that core.
CPU history panel
The height of the meter in each column corresponds to the intensity of CPU activity in that core. The red squares represent CPU activity per system process, while the green ones represent CPU activity per user process.
GPU panel
The blue squares show you how the video card is working hard in your Mac computer. It is not exactly clear what a blue square stands for. The GPU meter provides an insight into performance, but not specifically.
By default, the meters are not above all other windows active in your Mac. You can put the meters at the top by going to Window in the menu and then clicking on Bring All to Front.
If you want to close the window, you can either close Activity View or click on the red cross per meter.
I hope this helped you. Thank you for reading!
Also read: Make Mac faster.