Chapter in this post:
Some time ago I had a report in which I described how I did the Can empty the battery of my M1 MacBook Pro reasonably quickly. That was quite cumbersome and in retrospect only worked moderately well, since I was able to "only" bring the CPU load to around 130 to 140 percent. But there is a way to bring the processor load to almost 700 percent - and I'll describe the way here.
The whole thing works much easier and at the push of a button with a small app, which is "CPU stress test" is called. Here the name really says it all, because the little app does exactly that: It can keep the CPU busy with different numbers of threads and thus generate a significantly higher load than I managed with my few apps.
It is also nice that the app shows directly which CPU is installed in the Mac. "Apple M1" and "8 Cores" are correctly determined on my MacBook Pro (Apple Silicon).
The number of cores is a good piece of information for setting the amount of "threads" that the processor is busy with. For example, if you only have one thread, it would only be processed by one core. With Intel-based CPUs, twice as many cores are displayed here as the processor actually has. This is the case because each core can handle two processes at the same time through Hyper-Threading.
Choose the number of threads to run at the same time. Each thread will run on a separate CPU core. To run the CPU at 100% capacity, choose the same number of threads as there are cores.
For Intel based Macs, each core can run two threads at a time using Hyper Threading. This is why for example, a 4 core CPU will show there are 8 cores available.
With my M1 MacBook Pro, I should run 8 threads so that all cores are busy.
You can set the number of threads in the app to a value between 1 and 64. However, if you only have 8 cores and set 64 threads, you still don't generate a higher load than if you were to select 8 threads. This is because more than 8 processes cannot run at the same time and the CPU simply switches back and forth.
With my M1 MacBook Pro, with the choice of 8 or more cores, I was able to achieve a utilization of almost 700 percent. This is so high that the fans can even be heard in the device - and that almost never happens in everyday life.
With me comes the free and ad-free Mac app "CPU Stress Test" from Tunabelly Software used when testing MacBook Pro power supplies. When I measure the power with which the power supply units are charging, my MacBook Pro must have a battery level below 50%.
If I then connect the power supply and run the CPU stress test at the same time, then I have an impression of the maximum power that the power supply delivers during operation and I can check whether it gets very hot.
If you have any other ideas about what you can do with the software, I would appreciate your comment.
I also read yesterday that you can use the terminal command "yes" to load the CPU. However, this is much more cumbersome than simply doing it with the app.
The execution of the yes command outputs the character "y" with a line break or a character string with a line break defined by the user and given as an argument. This output repeats itself until the user terminates it (e.g. by executing the kill command). (Wikipedia )
With the solution with yes you either have to issue a chained command for multiple threads or open several terminal windows and start yes in each. That was too much typing for me personally ... I'm a Mac user and love apps and colorful buttons for nonsense. ;-)
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Jens has been running the blog since 2012. He appears as Sir Apfelot for his readers and helps them with problems of a technical nature. In his free time he drives electric unicycles, takes photos (preferably with his iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions for current bugs.