So, as many of you may have noticed, the 10.10.4 to 10.10.5 update was made especially easy by Nvidia. With any of the "must have Web Driver" cards you can simply run the 10.10.5 update, reboot, then on next boot you will find that only one display will work and you will likely notice that the screen redraws are slow and clumsy. The other noticeable thing is black horizontal lines running from bottom to top. This is a sign that the Nvidia drivers are not running. At this point you are just using the EFI. Now just run the Web Driver update and reboot.
You can either use our download link from the drivers page, or open the NvidiaDriver Manager Preference Pane and it will do the work for you.
Note that this only applies to folks already running 10.10.4. If you are running any earlier system and use the 10.10.5 Combo update you will likely have to use the other listed trick to turn off the driver before you run the 10.10.5 update.