Of course, the standard way of controlling CPU fans these days is with PWM, so he built a circuit which essentially converts the PWM signal from the motherboard into a phantom thermistor.
If you're already noticing lower performance than your particular CPU is capable of, a cooler upgrade might be overdue ...
However, that convenience comes at a price. If you want to upgrade an individual component of your laptop, such as the CPU, you'll typically face an uphill battle due to how modern laptops are ...