GPU running in half (Dying Light)

Friends, the problem is that in the game Dying Light the chip does not work at full capacity. msi afterburner (I use it to display information on the screen) shows the GPU frequency of 540 MHz, while the chip has 980 MHz in the drain. I tried to overclock, got an increase of 135 MHz, but in the game it is still 540 MHz. Updated firewood to zero sense, someone tell me where to go.
PS: I forgot, video card 740m 1024mb