Testing NVIDIA Optimus / DRI PRIME On Ubuntu 14.04

Overall, these results from Ubuntu 14.04 LTS show:

- DRI_PRIME is working fine out-of-the-box on Ubuntu 14.04 LTS for switching between the GPUs on the ASUS Zenbook Prime.

- However, right now using DRI_PRIME with NVIDIA GPUs on the Nouveau driver really isn't useful... Due to the lack of re-clocking, the GeForce GPU performance on Nouveau was consistently lower than the low-power Intel HD Graphics. The NVIDIA GPU in these dual-GPU laptops/ultrabooks is supposed to deliver greater performance, but that's only the case when using the binary NVIDIA driver and not Nouveau. The Nouveau re-clocking situation will be addressed in some future kernel update.

- When installing the NVIDIA proprietary driver on Ubuntu 14.04 LTS from the Trusty archive, the nvidia-prime package was easily installed. This allows for easy switching between the Intel GPU and the NVIDIA GPU with the proprietary driver. However, the switching isn't done in real-time.

- As expected, when using the NVIDIA binary driver with the GeForce GT 620M graphics processor, the performance was at its best. The power consumption was also higher, but that's to be expected, and even still this configuration was yielding the best performance-per-Watt for Linux gaming from this ASUS Intel ultrabook.