Not ini, cfg
\Program Files\Electronic Arts\Crytek\Crysis, create a new text file, and save it as autoexec.cfg. Add the lines I mentioned and see.
sys_MaxFps=30 will not work mostly, as far as I remember, but it's worth trying out.
The other two will work, but they will not give you lock at 30 FPS. But you should still try. And see if it serves your purpose.