I tried with lspci and inxi but I don’t know if those programs can even display that information
If you have a Nvidia card the info is for sure in Settings -> Nvidia X Server Settings.
And if I have AMD?
Well fortunately you don’t have one, do you 
I asked a lot of questions about Nvidia - true
This doesn’t mean that I have only Nvidia card
And seriously. I can’t anything about AMD cards. If it’s not possible then I’ll install Windows for a second but I would like not to 
Try a graphical system information viewer like hardinfo
No success here.
It seems that I’ll install Windows first time for about 5 years or more