Hello squalho,
If you sign in to My Grid - Device Manager and click on your Selected Profile, you can see whether or not you have selected Maximum Output. If you have not, then you are probably running on 60% throttle (use the CPU for 3 seconds, then idle for 2 seconds). The default is set to 60% to keep laptops from overheating, since many people are unfamiliar with computers and do not know how to check their CPU temperature.
If you change your profile, select SAVE to store the new value.
I checked the option and in fact it was set at 60%. Thank you a lot. In any case I won't raise this setting otherwise I would have heat problems as some people wrote.
Ciao