>> I'm not even sure what it means when they say that "C++ is 27% slower". << It means the author mis-read "how many times slower, ..., compared to the fastest

>> I'm not even sure what it means when they say that "C++ is 27% slower". << It means the author mis-read "how many times slower, ..., compared to the fastest programs." Compared to the fastest programs, not compared to the C programs. Compared to C programs, and Ada programs, and C++ programs, and JavaScript programs, and Fortran programs... that were faster.