My oldish Nvidia 4xxx GPU worked immediately and automatically on Linux Mint.
Your mileage may vary.
Edit: To be clear, I didn’t do any command line, or even change a setting. Mint just automatically detected my Nvidia GPU and got it working during the install while I looked at pretty pictures and new user tips.
(Disclaimer: Folks here have warned me this may have been some combination of luck and my Nvidia GPU being a few years old.)
When my Mint install finished, I searched for “Steam” in the Mint software center and clicked “Install”.
A few minutes later I was playing a game from my Steam library without any issues, without any config changes, and without any command line use.
Edit 2: On Linux, there’s a little Penguin icon in the Steam library filters. Click that, and it’ll only show your games that Valve is pretty confident will run without any issue.
It took me a few clicks to realize it did anything, at all. Very few of my games were filtered out. None of my games that were filtered out happened to fit in the first page of search results.
So at first it looked like penguin filter button did nothing.
Nice!
If you can afford it, I lately recommend getting a separate harddrive, and physically taking the Windows drive out, and putting a blank drive in, to run Linux on.
Windows has never liked to share, and has gotten worse (more aggressive preventing other operating systems from booting) with various integrations into BIOS for secure boot.
Also, either way, be sure to back everything up while Windows is still installed. It is much easier to lose data today, due to secure boot and full disk encryption being the default.
(Putting the Windows drive back in and resetting any BIOS settings should be enough, but it is possible that Windows will decide it wants the full disk encryption (FDE) password. I believe I have found my FDE password on the web through Microsoft account, but there’s just more that can go wrong, today. So I prefer to just have my files backed up so I can relax.)
(And be aware that it may not be possible to backup files directly from a removed Windows drive, if full disk encryption was enabled. There’s probably a utility for it, as long as you have the FDE password. But again, it’s much less effort to just make backups before pulling the Windows drive out.)
I’ve had the best experience booting to a fresh blank harddrive and installing Linux Mint on it, and throwing the Windows drive into a drawer until I find I want the extra drive space more than I want a retreat path to Windows.