Question core i5 9400f won't reach 4.1Ghz

[M Sajid]

why my i5 9400f won't reach 4.10Ghz? This processor base frequency is 2.90ghz and max turbo frequency is 4.10Ghz.No matter what i do with this processor the processor reach 3.89Ghz.i used handbrake to encode video but in the 100% cpu usage it doesn't go above 3.89Ghz

 

[jostegogar]

4.1 is 1 core. 3.9 is average clock speed of all cores