How disruptive is the GC?

[Temtaime via Digitalmars-d-learn]

I'm writing a game engine in D. Try to minimize allocations and 
that's will be OK.
I'm using delegates and all the phobos stuff. I allocate only in 
few places at every frame.
So i can reach 1K fps on a complicated scene.

GC is not a problem. DMD optimizes so ugly that all the math is 
very, very slow.
DMD gives me about 200 fps, when with LDC i can reach 1k.