Visual Studio Code Intellisense is very slow - Is there anything I can do?

Question

It turned out it was a particular VS Code extension for me.
Angular Language Service. Disabling this made it lightning quick.

Try this to see if it is a particular extension.

• Open Command Palette (Ctrl+Shift+P)
• Type in "Disable all installed extensions"
• Enable them one by one or in groups and test the intellisense speed

The problem might be with wrong setting configuration.
You might want to make sure these setting are on:

Controls if suggestions should automatically show up while typing

"editor.quickSuggestions": {
  "other": true,
  "comments": false,
  "strings": false
},

Controls the delay in ms after which quick suggestions will show up

"editor.quickSuggestionsDelay": 10,

Maybe it's Jedi. I mean its awesome but ... Tinkering with Jedi myself on bigger code bases I can confirm that it might be uber slow at times and pretty hard to figure out what the problems are... :/

Solution might be to switch to another language server! The VSCode Python extension has a "Language Server"-setting:

aka python.languageServer.

Pylance is MS own new language server. I just tried it and it all seems a little snappier. As of today this is tagged as Preview. So there might be improvements around the corner.

My answer's for c++ but still kinda related.

I'm using the C/C++ extension from Microsoft, and when I switched its Intelli Sense Engine setting from Default, with "context-aware results", to Tag Parser, with "'fuzzy' results that are not context-aware", it immediately started showing IntelliSense options instead of delaying for 5+ seconds.

So maybe check the particular options of your language's or environment's extension(s).