The Go program allocates a new item on every line instead of allocating a single struct and just passing a pointer into unmarshal, which would be way faster. There's some claim of "doing async style programming" but the Go code doesn't parellelize anything, so... not really a fair Go entry there. The input file is also not supplied.

edit: not to mention there are things like adding individual sums multiple times that suggest that the author didn't check the output to verify that all programs arrived at the same output...