Clarification on PRIME Synchronization, prime-select & Intel GPU xorg.conf "TearFree" option


I’m hoping to get some clarification on screen tearing solutions (i.e. PRIME Synchronization) and how using that feature interacts with the ability to use prime-select to switch back to using just the Intel integrated GPU.

I’m running 18.04.04 with a laptop that has switchable graphics: intel & GTX1650. 435 NVIDIA driver version. In the BIOS I have options for “Switchable Graphics” or “Dedicated” which I have set on “Switchable Graphics”

prime-select is currently working and significant screen tearing is present when on the NVIDIA GPU. There is tearing on the Intel GPU but much less noticeable (noticeable when dragging windows, watching videos, etc…)

I have not yet started down the road of setting up PRIME Sync because I want to get a better understanding of all this first.

My goals are:

  • no screen tearing when using Intel integrated GPU (my primary usage GPU)
  • no screen tearing when using NVIDIA GPU (occasional usage for gaming / game dev tools)
  • retain the ability to use prime-select to switch between GPUs and have the rebooot go smoothly without the need to modify configuration in a text-mode TTY after switch & reboot to get X or GDM to work
  • retain low power usage & low fan usage when using Intel GPU

I’ve read up on this and I understand that the fix for NVIDIA tearing is the options nvidia-drm modeset=1 option & enabling PRIME Sync

And on the intel side it’s creating an xorg.conf for the Intel GPU with the “TearFree” option.

However, I’ve seen posts from people indicating that the two fixs above are incompatible. Basically that if the intel xorg.conf exists and you switch back to NVIDIA with prime-select X (or gdm?) fails to start. And that you need to remove the intel xorg.conf when using NVIDIA GPU & put it back in place when going to Intel.

So my questions are:

  1. When using PRIME Synchronization can I still freely switch between Intel & NVIDIA using prime-select?
  2. If yes, will PRIME Synchronization fix the screen tearing on the Intel GPU as well as the NVIDIA side (making the "TearFree" xorg.conf unnnecessary)
  3. In terms of power management, when using PRIME Synchronization with the Intel GPU selected is my power usage still in the same ballpark as when using the Intel integrated GPU with the "TearFree" xorg.conf and PRIME Sync disabled? Or is the dedicated GPU always involved somehow with PRIME Sync making that solution use more power than 'vanilla' integrated GPU

If the questions above contain fundamental misunderstandings about how this all works thank you in advance for correcting any misconceptions I may have.