Have a look at the Release Notes. It tells exactly what is going to happen, and IMHO, it is a step in the right direction, not a problem.
The fglrx driver is now deprecated in 16.04, and we recommend its open source alternatives (radeon and amdgpu). AMD put a lot of work into the drivers, and we backported kernel code from Linux 4.5 to provide a better experience.
When upgrading to Ubuntu 16.04 from a previous release, both the fglrx driver and the xorg.conf will be removed, so that the system is set to use either the amdgpu driver or the radeon driver (depending on the available hardware).
More information is available at https://tjaalton.wordpress.com/2016/03/11/no-catalystfglrx-video-driver-in-ubuntu-16-04/
I wrote a complete article on how to install drivers and cuda for RTX 2080 series GPUs on Ubuntu, mainly because it can be a time consuming task for some(most?) users. You are advised to follow the article along with the following answer.
I observed the same issue with both
Ubuntu-16.04 the machine hadn't found the correct Nvidia driver and it had been using open source Nouveau display driver. Hence you're required to download and install the proper driver from Nvidia.
Now install the drivers as follows.
1) cd Downloads/
#(NVIDIA-Linux-x86_64–410.57.run #output of ls)
3) chmod +x NVIDIA-Linux-x86_64–410.57.run
#(to get permission to execute the run file)
4) sudo ./NVIDIA-Linux-x86_64–410.57.run --no-x-check
--no-x-check flag is important. Otherwise you will have to disable the
x-server and log out from the GUI.
Once the drivers are installed reboot the machine and verify the installation with
nvidia-smi command on a terminal. It will show you GPU and installed driver information.
The next part is installing cuda which can be a pain at times. You will have to log out from the GUI and perform all the actions on a terminal.
Download your relevant cuda run file from this link. Then create a file called blacklist-nouveau.conf in your home directory and add following lines to this file.
options nouveau modeset=0
Now we have to log out from the GUI by pressing (ctrl+alt+f1) to install cuda. Enter your username and password to go to the terminal.
Now follow the steps below.
1) sudo service lightdm stop
2) sudo -i
3) sudo cp /home/avin/blacklist-nouveau.conf /etc/modprobe.d
#change avin with your user name
4) sudo update-initramfs -u
6) cd Downloads/
7) md5sum cuda_10.0.130_410.48_linux.run #(Optional)
8) sudo sh cuda_10.0.130_410.48_linux.run
Cuda installation wizard will appear. Follow apparent steps, along with the article.
Once the installation is finished run
reboot on this terminal.
Once the machine is rebooted add cuda path to the
1) sudo gedit ~/.bashrc
2) Add following 2 lines at the end of the .bashrc file
3) source ~/.bashrc
nvcc -V on a terminal which should yield an output as follows.
Now that the drivers and cuda are installed you might want to install tensorflow gpu version. Here is a good tutorial for the very same task.
Disable Secure Boot in BIOS. With Secure Boot enabled proprietary drivers will never load. Then run in a terminal
The 367 driver is a recommended by Nvidia LTS driver.