Fog test shows how the new MacBook Pro cooling system moves heat

Fog test makes the airflow visible

Apple says the latest MacBook Pro has a completely redesigned cooling system that delivers what the company calls incredible sustained performance. That claim was hard to verify with benchmarks alone, but a simple experiment now offers visible evidence.

According to 9to5Mac, Macworld spotted a YouTube video by Geekerwan that compares the new model with the previous mini-LED MacBook Pro using a fog machine. With the fans running on each machine, the fog traces the path of the warm air.

In the older model, heat escapes both out the sides and up through the display. In the new PROLED XDR model, the air is pushed towards the back of the device through the hinge.

Why thermal design matters

The performance of any laptop depends on more than raw chip power. When a device gets too hot, it reduces clock speeds to protect the hardware, a process known as throttling. In the worst cases, a chip only reaches its theoretical maximum for a short burst before performance drops sharply.

That makes thermal management especially important in a portable machine, where space for cooling hardware is limited. Apple says the new thermal architecture allows the M5 Pro and M5 Max chips to sustain high performance even in a lighter design.

Redirecting heat away from the display

A notable detail in Apple's description is that the new design redirects warm air away from the display. The fog test appears to back this up, showing air leaving through the hinge at the rear instead of rising towards the screen.

The video does not include performance measurements, so it shows the direction of airflow rather than proving better sustained speeds. Apple's claim of improved performance remains the company's own statement, supported visually but not independently benchmarked by the clip.

What it means for buyers

For anyone choosing between the previous and new MacBook Pro, the test offers a rare look at a change that is normally invisible. Sustained performance matters for tasks such as video editing or compiling code, where the chip works hard for long periods.

Readers who want quantitative results may prefer to wait for independent benchmark tests, which can measure how long the new machines hold peak performance before throttling. For now, the fog test gives a clear visual answer to a question Apple raised at launch.