What is the quickest way to draw something in c++?
I mean, let's say i have created a window, and now i want to draw something on it. It doesn't have to be sprites with textures. Just squares with colors is good enough.

I've heard about OpenGL and DirectX11, but i don't know which one is faster.

For those of you wondering why i need to know this, i am programming a galaxy collision simulator, and when rendering all the particles i need to draw all particles as quick as possible or it will lag ALOT. I first wrote this program in visual basic and it rendered with DirectX 8. But that was is wayyyy to slow. So now i'm learning C++ and hope that it will operate faster than visual basic.

tl;dr: What is the fastest rendering method?