New PG278QR getting 143HZ instead of 140Hz Why? Please help

hello community

i had an ASUS PG278Q, everything was fine but i have some ghosting and asus give me back my money, now i bought the new PG278QR, and in all games i get a maximum of 143hz or 119hz and so on, in window mode the refresh rate is 144hz, so my question is, how do i solve this…i can tell you that im an advanced user, i have my nvcp configured to work with my GTX980M, i have a Clevo P771DMG with an i7 6700k and 32 of ram
thank you in advance