Introduction
For using Optimus hardware in GNU/Linux environments, nVidia's official PRIME package was the to-go solution in recent times. Bumblebee, the open-source implementation of Optimus isn't considered too efficient, sometimes even slow. I found a new way of using these solutions together, resulting in unexpectedly high performance.

Hardware and software
Asus G46VW (i7-3630QM with Intel HD Graphics 4000 and GTX 660M)
Ubuntu 14.04.4 MATE 64-bit

The idea
A known issue with PRIME is that it doesn't let the Intel GPU synchronize each frame with the built-in display if the nVidia card is selected, resulting in massive tearing while watching videos or playing games. Solving this was my primary intention, this is why I started fiddling around the drivers and different packages.
I started out on a system with PRIME set up and working properly. Since I didn't care much about losing the installation, I acted brave and added Bumblebee to the system. It worked fine. When I removed nvidia-prime (in order to see if Bumblebee even works), I got to the blank login screen that shows up when video drivers fail to initialize. So from a terminal I reinstalled it and worked again like a charm. From that point on I started experimenting to create a tutorial for it.

Method
In order to achieve this (tested it multiple times) I followed these steps:
1. Install Ubuntu MATE
2. Run all the official updates
3. Open a terminal (Ctrl+Alt+T) and run these commands:
Code:
sudo apt-get install nvidia-352 nvidia-settings nvidia-prime
sudo reboot
4. Open a terminal again:
Code:
sudo apt-get install bumblebee bumblebee-nvidia primus linux-headers-generic
sudo reboot
5. One last time:
Code:
sudo prime-select intel
sudo reboot
6. You're ready to go.
7. When launching something graphically intensive, use the term “optirun”, e.g.:
Code:
optirun steam
Performance
Originally I expected Bumblebee to be slower, but it isn't, according to the numbers.

1. GRID Autosport benchmark mode, ultra settings, full screen@1366x768, no AA
Running with optirun (prime-select intel)
average FPS: 32.87
min FPS: 25.29
max FPS : 46.21

Running without optirun (prime-select nvidia)
average FPS: 32.03
min FPS: 25.65
max FPS: 43.45


2. Unigine Heaven Benchmark 4.0, medium quality, full screen@1366x768, 2xAA
Running with optirun (prime-select intel)
score: 952
average: 37.8
min: 9.4
max: 65.5

Running without optirun (prime-select nvidia)
score: 925
average: 36.7
min: 18.0
max: 64.0

Issues
The only problem I had was that once I used optirun by accident while prime-select was set to nvidia. The application ran fine, but the system froze after exiting and I had to force reboot. Note, that this usage scenario isn't intended and shouldn't occur if the tutorial was followed properly.

Conclusion
The framerates produced with the explained method are very close to the ones I got by using the traditional PRIME solution, but when using optirun, every frame is synced to the screen, resulting in a more enjoayble overall experience.
Even if this is Bumblebee only and has nothing to do with PRIME, this guide may help others set it up, since nvidia-settings and nvidia-prime configure everything for Bumblebee, making it easy to use for anyone.