IntelliJ IDEA Performance Issue - Multiple Project Windows Hang During Project Analysis/Indexing

Description:

I am experiencing a performance issue with IntelliJ IDEA where multiple project windows become unresponsive when one project is undergoing analysis/indexing.

Issue Details:

• When IntelliJ IDEA is analyzing/indexing one project (enabling smart features)
• Other IntelliJ windows with different projects become hung/unresponsive
• This appears to affect all open IntelliJ instances simultaneously
• The hanging persists until the analysis/indexing of the first project completes

Environment:

• IntelliJ IDEA Version: IntelliJ IDEA 2025.3.2
• Operating System: Windows 11
• Java Version: Java 21.0.7
• Maximum RAM/Heap to IntelliJ: 30GB
• Number of concurrent projects: 2

Performance Configuration Note:
I have allocated 50% of my system RAM (30GB) to IntelliJ IDEA specifically to avoid performance issues, as these hangs are extremely disruptive to my workflow. Despite this generous memory allocation, the cross-project interference still occurs.

Questions:

1. Is this a known limitation where IntelliJ IDEA analysis/indexing operations block other project windows?
2. Are there any configuration settings to prevent this cross-project interference?
3. Is this related to shared resources or memory allocation between multiple IntelliJ instances, even with abundant RAM allocated?
4. Are there recommended best practices for running multiple IntelliJ projects simultaneously?
5. Could this be related to CPU-bound operations rather than memory limitations?

Expected Behavior:
Each IntelliJ project window should operate independently without affecting the performance of other open projects, especially given the substantial memory allocation.

Actual Behavior:
Analysis/indexing in one project causes all other IntelliJ windows to become unresponsive, despite having 30GB of RAM allocated to IntelliJ.

I would appreciate any guidance on whether this is expected behavior and if there are any workarounds or configuration changes that could resolve this issue. The current behavior significantly impacts productivity when working on multiple projects.

Thank you for your assistance.