HD7750 noises at load

When i play games or hd songs i can hear faint buzz from my gpu....when i play 720p or 1080p songs i cant hear with speakers on..when i put ear on gpu it is like electric buzz(chir chir like) but from distance it is hummmm....it also happens when playing games....but speed(frequncy) changes....i watched in ccc that at playing songs my gpu clock and memory clock rise to full but activity is near 20-25%....is this normal???

Your GPU clock changes by itself ?

Could be the fan.

yeah normally meter is at 150 but when grapphic activity it rises to 800.........

and its not fan because i ran fan at 100% speed but no such sound...normally fan runs at 45%....