F# Intellisense eats my CPU

When I open my project and afk, CPU usage is near 0%.

Sometimes when I work for a while, and then afk, CPU usage doesn't decrease to 0%, still remains at 5%.

Although it's low, my fan don't think so.

## **Repro steps**

I don't know?

Open a project, randomly delete something and undo?

Or open a HUGE project, and open as many tabs as you can?

## **Related information**

Actually I captured a flame graph. It says

https://github.com/dotnet/fsharp/blob/cd4fdf2584c4c8feb9eaea2de02c67ac7b146cd7/src/Compiler/Utilities/Caches.fs#L273-L305

these two functions consumes 80% of the 5% CPU usage.

I can't investigate further, sorry.