That's a very ignorant thing to say. Look at Valve. They just showed they can get more FPS out of a game in Linux using OpenGL than on Windows using Direct3D.
... Because Linux = OSX...?
Just because they both run on UNIX doesn't mean they are mostly the same.
Really, that's just a very ignorant thing to say.
EDIT: Oh, and if you're saying that it's about OpenGL vs. Direct3D, then listen up:
Linux can run in a <10kb file.
Windows has to run in a >1GB file.
Linux:
- Is designed to be light.
- Is extremely small.
- Does not take up as much RAM.
- Does not have proprietary drivers.
Windows:
- Has over a hundred tasks to deal with at once
- Takes up a fair amount of RAM (512-1024MB)
- Is not made to be specifically small
- Has specially-made proprietary drivers
Overall, I find your argument(?) very ignorant.
~ General Argument. ~