In general, Julia has similar performance characteristics to other fast compiled languages (Fortran/C++). There are some performance differences do to different semantics (eg bounds checks by default), but Julia is good about giving you the ability to opt out of these easily. There are also definitely places where Julia makes it a lot easier to get better code by making it a lot easier to use better algorithms, so in general, simple Julia code tends to be similar/better performance than Fortran/C++, and optimized Julia code tends to be about the same speed as Fortran/C++, but with 10x less code.