I have a problem with Xubuntu 18.04.
The problem is, when I do something that uses a lot of memory (like watching YouTube videos, opening multiple tabs on Chromium, opening a tab on Chromium, or loading a heavy website), the screen doesn't update for 5-8 seconds, get filled with black for 1-2 seconds, then displays the GUI again (sometimes it doesn't update eventually, then I have to restart my PC). On YouTube, when I open a video, it does the previous sequence 2-4 times continuously!
Besides Chromium and YouTube, that happens regularly (every 30 seconds to 3 minutes).
What do I do to prevent this problem? Tell me what information you need, and I'll give it to you.