What is the use of nvidia-prime?

Yesterday, I was very excited about initial support for optimus using nvidia-prime package on Ubuntu 13.10. It seemed to be the way to replace my bumblebee + hybrid-screenclone configuration, since there is no patch available for the intel video driver that ships with Ubuntu 13.10. After hours of trials and errors, I only got a system where external and LCD displays randomly works or not, LCD screen flickers, window decorations are broken, and display randomly freeze. Not really usable so far...

But now my question is: even if nvidia-prime was working as expected, why would I want to use it? The reason optimus is there is to allow switching off discrete card when I don't need it, to save on battery power. But with nvidia-prime, it seems discrete card is always powered. Why someone would want to use an unstable optimus support that doesn't save power?

The conclusion: if I need to save batteries and I don't need external display, I just need to boot with display adapter set to integrated in the BIOS. If I need external display and I'm connected on sector, I just need to boot with discrete display adapter. And if I need to boot in Windows, I just need to put back the display adapter setting to optimus.

For nvidia-prime to work, remove bumblebee and bumblebee-nvidia with a --purge first. Reinstall nvidia driver with nvidia prime. nvidia-prime uses the implementation of Nvidia's Optimus technology but in this case, the nvidia driver always stays on regardless of system load and the intel driver is only used as a sink. The advantage of this is better framerates than bumblebee but of course more battery consumption and heat as well. With kernel 3.12 the automatic switching like in Windows would be implemented.

I am not sure if this answers your question. But i find nvidia-prime could be a welcome relief to the crowd who have an nvidia card with optimus , and have no way to switch between an optimus setting/ non optimus setting like you can . In case of my laptop , which is the Dell XPS 15 L502X, i cannot switch modes in BIOS , and nvidia-prime let me use my nvidia card for a while , until i found it to be really a pain with an external display plugged in (broken window decorations mostly) .

I am guessing that this will improve once new updates roll in though. Hope that gets rid of some confusion.

PS : Also , as someone who might be interested in using the features of the nvidia card than not having any access to it , i wouldnt mind the power trade off. I will be a happy man if i can just use my nvidia card and for instance , use the openGL 4+ features :)

Edit - I have installed Ubuntu 14.04 , and nvidia-prime (0.5 is the latest update) once installed , lets you switch between the intel/nvidia graphics processor. The nvidia-settings app lets you choose this as well (i m not sure if nvidia prime is essential for this, but i kept it anyway). So looks like all my optimus issues are solved for the moment. Thanks to this link