On my machine D is faster than his c++ version, so It does look good. I use his own repository so I do not know why his results are so different in my case:
his c++ version with gcc:
real 0m0,021s
user 0m0,021s
sys 0m0,000s
his D version with DMD:
real 0m0,018s
user 0m0,015s
sys 0m0,004s
his D version with GDC:
real 0m0,015s
user 0m0,006s
sys 0m0,010s
his D version with LDC:
real 0m0,030s
user 0m0,025s
sys 0m0,005s
LDC is slower because on my system it use shared phobos library, so it takes some time to load it.
all others (gcc,gdc and dmd use static libs)
When I use shared phobos for dmd, I get
real 0m0,032s
user 0m0,024s
sys 0m0,009s