Despite installing NVIDIA Web Drivers, 10.3 keeps reverting back to OS X's graphics drivers. What do I do?

Everything is working flawlessly but for some reason I can't get NVIDIA Web Drivers to boot. I installed them and switched from OS X drivers to NVIDIA, but every time I restart, it switches back to OS X.

I've tried adding an nvda_drv=1 bootflag but that does nothing.