Hey there! I totally get where you're coming from—Ubuntu 17.10 switching to GNOME Shell as the default was such a relief for folks who already had it installed manually, but those random CPU spikes are definitely frustrating. Let's walk through some common fixes that worked for many users back then:

• Disable GNOME Extensions first
  More often than not, a misbehaving extension is the root cause. Grab GNOME Tweaks if you don't have it: sudo apt install gnome-tweaks. Open it, head to the "Extensions" tab, and toggle all extensions off. Wait 10-15 minutes to see if the spikes stop. If they do, re-enable extensions one by one until you find the culprit (common offenders included outdated weather extensions or window management add-ons).

• Turn off fractional scaling
  Ubuntu 17.10 had early, buggy support for fractional display scaling. If you're using a scaling percentage that's not a whole number (like 125%), head to Settings > Devices > Displays and set it to 100% or 200%. This fixed CPU spikes for a lot of users with high-DPI screens.

• Update your system fully
  Even though 17.10 is end-of-life now, when it was supported, Canonical pushed updates that addressed GNOME Shell CPU issues. Run these commands to make sure you have all the latest patches:

  sudo apt update && sudo apt upgrade
  

• Pinpoint the problematic process
  When a spike hits, open a terminal and run htop (install with sudo apt install htop if needed). Look for gnome-shell or related processes (like mutter, the window manager) using high CPU. Sometimes it's a specific task (like a notification daemon or search provider) triggering the spike, which can lead you to a more targeted fix.

• Reset GNOME Shell configuration
  Corrupted config files can cause all sorts of odd behavior. To reset your GNOME settings to default (note: this will erase custom shortcuts, panel layouts, etc.), run:

  dconf reset -f /org/gnome/
  

  If you want to back up your current config first, save it to a file:

  dconf dump /org/gnome/ > gnome-config-backup.txt
  

One last thing: try switching to the Xorg session instead of Wayland (Ubuntu 17.10 used Wayland by default for some hardware). At the login screen, click the gear icon and select "Ubuntu on Xorg"—Wayland had some teething issues with CPU usage in early releases.

内容的提问来源于stack exchange，提问作者Cyber_Star