To test it, it must be done in time. I can just say that I chose compared instead of the fan compared to my computer. It rises or uses flat. Very good. Drawback, it does not stop automatically when put on hold. And it's really unfortunate that occupies a USB port without compensation. After a few months of use, I must add that it is not so good. Fragile, even when we do it live nothing but a laptop over him. First exchange because the fan was noisy ... And now with the new product, any more current, suddenly, overnight. As for cooling, passable.