Why does the video card fan speed change frequently?

Recently installed an overclocking three 7010 graphics card fan, but installed, view graphics card fan speed is very unstable, has been in the 3000RMP-6000rmp between frequent changes, did not hear an abnormal sound, graphics card temperature is also considered normal, which in the end is why? Jining door-to-door repair computer repair personnel: part of the market can be adjusted according to the cpu or gpu load of real-time adjustments Recently installed an overclocking three 7010 graphics card fan, but installed, view graphics card fan speed is very unstable, has been in the 3000RMP-6000rmp between the frequent changes, did not hear the abnormal sound, the graphics card temperature is considered normal, which in the end, why is it? The newest addition to the lineup is the newest addition to the lineup.