Problem about result of PCIe bandwidth test

[didiHe]

I tested the PCIe bandwidth using 1660ti, the result is as below:

The theorical band width is 15.754GB/s（gen3 x16) the test result is about 25% lower than the 15.754.
Why is the test result lower so much of the theorical para?

[lf2050]

const bool pinned=false may be usefull to you.
suggest try this option.