Hi,
I am using Antergos on my laptop (Alienware 17 R3) which uses a GTX 970M and an Intel GPU.
The HDMI output is hardwired to my Nvidia GPU and I have no possibility to switch off any of these GPU in the BIOS.
For a presentation (using a second screen) I need to be able to use the HDMI port, unfortunately this isn’t that easy as I thought.
I tried to follow the Arch Wiki https://wiki.archlinux.org/index.php/bumblebee#Output_wired_to_the_NVIDIA_chip on how to use the output, however the performance of the second screen is bad and has huge framdrops, so you can’t game on that screen.
I also thought about using sth other than Bumblebee like prime but the there isn’t an great ressource for using Prime on Arch (at least I haven’t find any good). The Arch wiki doesn’t provide that much information.
I would just like to have sth similar to the prime stuff on Ubuntu where I can easily switch to the Nvidia GPU and then I can also use the HDMI port.
Hope someone can help :)

EDIT:
Looks like you can’t game on the second screen if you’re using bumblebee.
I recommend the default Nvidia Optimus setup on the Arch Wiki:
https://wiki.archlinux.org/index.php/NVIDIA_Optimus#Using_nvidia , also mentioned in this thread https://forum.antergos.com/topic/2760/nvidia-prime/9 by @Doaxan .

Tip: If you do this setup, you maybe have to add xrandr --dpi 96 (as described in the Wiki), otherwise you will have very small fonts. Now only the Nvidia GPU works (for me), however you can now use any additional screen with easy plug’n’play like in other distros e.g. Ubuntu if you switched to the Nvidia GPU mode.

I’ve also added instructions on how to get rid of screen tearing which can be found in the Arch Wiki:
https://wiki.archlinux.org/index.php/NVIDIA_Optimus#Tearing.2FBroken_VSync

If there are any questions, please ask, at this moment I’m still into this topic and can maybe provide help ;)