Alienware m18 CPU always on max frequency while idle

Hi

I just bought an Alienware m18 r1 laptop with an AMD r9 7945hx processor. I noted from the start that the processor frequency never drops below 5 GHZ even in idle with fans often at 70%.
I used the power management options that come with windows11, and updated all drivers including the bios one, without success !
Another problem - I don't know if it is related to the previous one - is that computer refuses to go to sleep mode or "wakes up" by itself...

Is there a known solution to this problem?

Thanks in advance