[avasthe]

Go GC has some smart people working on it too.

And Go, by the virtue of having less features, has to allocate quite more. Eg: Go doesn't have lazy ranges / streams. Dynamic dispatch using interfaces has to allocate memory on heap.

Also, I expect D standard library to be optimized for Non-GC use case at least a part of it, because that's one of its use cases.

Compiler's escape analysis matters too. I'm told Go's escape analysis is not very sophisticated.

Last, it may be case of missing features in D version as a comment mentioned.