Apparent problem with GC not collecting on Windows

[Michael]

1. Can be solved using allocators 
http://dlang.org/memory.html#newdelete and 
http://dlang.org/class.html#ClassAllocator (here deprecated)?
2. Why with
class Too
{
private uint[] pp;
    this(int s)
    {
       pp = new unit[s];
    }

alias pp this;
}

Only 3 iterations before out of memory exception?

3. Why it helps?

foreach (i; 0 .. 10) {
         file.rawRead(data);
     }

GC.free(data.ptr);


Win 8 Pro, 64 bit.