How to update all the drivers to latest version(bootcamp)
The important Apple drivers which Windows invariably doesn't have updates for are Facetime camera, Apple keyboard/trackpad/mouse, and the IR receiver.

Beyond these you can update any drivers that MS has to offer through Windows Update, and I've had no issues with downloading video drivers directly from nVidia. Always create a restore point so you can backtrack if you install something that doesn't work as well as it should, link to MS help page here.