Desktop or GUI environment on a server

Q: I installed Ubuntu Desktop on my server and it:
     A: Performs slowly
     B: Has weird GUI issues
     C: Some other problems

A: The short answer is that Ubuntu Desktop is not considered a certified and supported solution on server grade hardware.

Ubuntu desktop has some pretty heavy graphics processing requirements. Servers often provide a bare minimum of graphics processing capability and that is often in the form of shared RAM and shared CPU cycles. Desktops usually have completely dedicated GPUs, or at least more capable discete GPUs that do a much better job especially in 3D accelerated graphics scenarios.

Additionally, older servers (and perhaps even newer ones) usually have low-end display adapters that may not have 3D acceleration, meaning any modern Ubuntu running a heavy and resource intensive desktop environment will most likely function pretty poorly.

So while Ubuntu Desktop may work on server grade hardware, it may not work well and is not something considered supported.

If you must have a GUI on your server, rather than Ubuntu Desktop, you may want to try one of the Ubuntu variants with lighter GUI requirements like Xubuntu or Lubuntu, or try installing a lighter GUI environment.

There is a list of Ubuntu Flavors here: https://ubuntu.com/download/flavours

One of those may give you better results than a Gnome3 or KDE based desktop will.