Hi!
I am new to linux and my installed gpu, gtx 760 i broken so today I am going to switch to a gtx 970. I have the nvidia 470 driver installed and I am running KDE. Do I have to do something before the gpu replacement or is it just plug and play?
//Simdim
I have the 960 GTX. so it’s not far off. Here’s what I would do:
Identify the current one:
mhwd --listinstalled
Uninstall the current one:
sudo mhwd --remove pci <driverIdentifiedPreviously>
Install the nouvea drivers:
sudo mhwd --install pci video-linux
Reboot if there were no errors. If all looks good upon rebooting, shutdown and turn off the computer. Switch the GPUs. Turn the computer back on. It should, in theory at least, boot into the normal desktop possibly without any effects. Reinstall the drivers for the GPU:
sudo mhwd --auto pci nonfree 0300
If no errors, hold your thumbs, cross your heart, say a little prayer and reboot.
That should in theory be it.
Yes, I know it’s probably over-cautious, but I prefer safe, rather than sorry,
Thank you! I will do this now 
!
After a while I got it to work!
The problem was that I could not remove the driver as long as the desktop enviroment was running.
Thank you!
This may also be necessary in other situations. Especially if there are major updates for the DE (XFCE, GNOME, KDE) used.
Welcome to the forum! 
Sorry, we can’t help with that. 
The 470 series driver will work with both cards.