The first thing I would try is the standalone BOINC package
found here. It's working fine for me and you won't have to worry about groups, permissions and other Linux nonsense.
You just won't be able to run it simultaneously with the one from the repo.
When I was running Lubuntu, I think there is a package for BOINC to detect the GPU. If you search for BOINC, you should see something about GPU detection in the description.
Found it: boinc-client-nvidia-cuda
But I'm not sure it's really necessary, I do not have it installed on my current Ubuntu machine and it's crunching just fine. As we both have Maxwell cards, you shouldn't need it either.
I ended up
following this guide, except I am using driver 375.82. I did this:
sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update
And was then able to install the 375.82 using the guide instructions.
There is
further discussion here and a couple step-by-step posts.
I have run into a problem several times with different distros where you can't log in after rebooting, the Nvidia driver breaks the log in screen somehow. On my system with Ubuntu, I had to disable a secure boot OS Windows setting in the UEFI, or maybe set it to Other instead of Windows, I forget now. Anyway Ubuntu was stuck in a loop, I'd log in and it would flash a black screen and then back to the log in screen.
Good luck, hopefully this gets you pointed in the right direction.
