Lenovo Thinkpad E 560 graphic card r7 m370 only using default clock speed of 875 mhz, although this graphic card has a boost speed of 960 mhz. How can i make it run at full boost speed?

How can i use my r7 m370 at full specified 960 mhz clock instead of just 875 mhz default clock? It translates to more than 10 % performance increase and i need it in games!