Severe Lagging/Performance Issues in Latest IntelliJ IDEA Versions (2025.x+)

Hi Kimjisoo4953, thanks for reporting this. I’m really sorry you’re experiencing such issues.

To help us narrow it down, try temporarily disabling non-bundled plugins and increasing IDE memory in Help | Change Memory Settings.

If the issue persists, could you specify:

• Your OS + IntelliJ IDEA version(s) affected
• JDK version and project setup (Maven/Gradle, approximate size)
• When exactly the lag appears (typing, completion, indexing, switching files, etc.)

When the slowdown happens, please also collect:

• Help | Diagnostic Tools | Start CPU Usage Profiling, reproduce the lag, stop and save the snapshot
• Help | Collect Logs and Diagnostic Data

If you share these using JetBrains Upload Service, we can analyze what’s actually causing the regression.

Regarding AI and completion quality, thank you for the honest feedback. If you can share a few examples where suggestions feel slow or irrelevant, that will help our teams improve it.

We’ll dig into this as soon as we have your logs.

I have noticed the exact same thing after upgrading from PhpStorm 2025.2 to 2025.3 this morning. I'm on macOS 15.5 (Apple M2 Pro). Previously scrolling vertically in the editor or typing was smooth however now it feels blocky/chunky. Just before the upgrade I had modified the memory from the default of 2048 to 3072 without change. I'm considering a downgrade until the issue can be identified/resolved. 

Appreciate that this thread isn't about PhpStorm however I have uploaded the diagnostic data (Upload id: 2025_12_08_8GdXfHnJaUV2GLE9YT2xHF)

Same Problem here using Linux.

The whole UI (IntelliJ Ultimate) is lagging massivly. Just click the tab of an other open file - I takes about a second to refresh the window.

In all the years I never hat an IntelliJ update like this - practically unusable.

 I'll downgrade to 2025.2.5 for now which runs perfectly …

I’m on Ubuntu and experiencing severe lag with IntelliJ IDEA 2025.3 as well.
The entire UI feels sluggish — even switching between open file tabs takes too much time to refresh.
Earlier versions run smoothly, but 2025.3 is practically unusable for me too.

Quick update: the issue seems related to the UI theme.
When I switch from Island Dark to the regular Dark theme, all the lag completely disappears and IntelliJ IDEA 2025.3 works normally again.
Might help others experiencing the same problem.

Had the same problem on Ubuntu and switching off the Island Dark theme fixed it as well. I tried to do a CPU profile in the tool but it output a empty file for some reason. When I looked at top however, I was seeing huge CPU spikes when I used the editor. I have 128 GB of RAM on my machine and the IDE has access to half of that in the heap settings. When I was running it had 70GB free so it seems to be isolated to a CPU utilization issue.

Also I switched to the Color Scene of Island Dark without selecting the theme and still working fine. If you like the appearance of that theme I would suggest that configuration.

Tim Philips, I reviewed the thread dumps and CPU snapshot you shared, and it looks like there is an issue related to the Metal rendering pipeline.

As a workaround, you can try disabling Metal rendering by adding the following line to your Help | Edit Custom VM Options file:

-Dsun.java2d.metal=false 

After adding this, please restart the IDE.
Let me know how it goes. If the issue persists, we’ll investigate further. 

Thank you Ilnur Galimov that has resolved the issue.  Will this be something that is addressed in an upcoming version or will I always need to retain this configuration?

I saw reference above to Island Dark/Light theme and hopefully it helps identify the root-cause - I'm using the default Light theme.

I applied the suggested workaround -Dsun.java2d.metal=false and it improves overall performance — the IDE is much smoother now.
However, there is still a noticeable slowdown when using the Island Dark theme. It’s better than without workaround, but not nearly as fluid as with the regular Dark theme, which remains perfectly smooth.

Tim Philips, there’s a known issue with Metal rendering in the JetBrains Runtime (JBR). We’re continuously working on improving JBR, and you can expect performance improvements in future releases. In the meantime, I recommend keeping this setting enabled.

Axel Mueller, are you using the Islands Dark theme? If so, could you please try changing to the regular Dark theme to see if that fixes it. If the issue persists, please collect the logs by going to Help | Collect Logs and Diagnostic Data and share them using JetBrains Upload Service.

Francesco Limberti, I'd like to take a closer look at this. Could you please enable the Islands Dark theme and collect the logs in Help | Collect Logs and Diagnostic Data? Please share them using our JetBrains Upload Service. Thanks!

Ilnur Galimov here the diagnostic data uploaded Upload ID: 2025_12_12_cCnDzVVEVjzmJT3s6DzA4n (file: idea-logs-20251212-1750353428876130332396528.zip)

I’m using WSL and experiencing significant lag with IntelliJ IDEA 2025.3. 

Git operations are extremely slow, making the IDE nearly unusable. 

Although I appreciate the new UI, I have to downgrade to 2025.2.3 until these issues are resolved.

Same problem described here. Changed from Island Light to Light,  problem persists.

Upload ID: 2025_12_13_Mw9wVdVtuHKT1TxYGUeunx

Freezes took place at 05:31 and 05:37 Pacific Time (GMT +8)

Follow-up: the Help | Edit Custom VM Options strategy described above, disabling Metal, fixed the frequent-freeze problem. 

The performance issue with the Islands theme is currently under investigation: https://youtrack.jetbrains.com/issue/IJPL-222923.
Please upvote the issue to help us prioritize the fix.

For those who switched away from the Islands theme and saw improvement: we need your help to investigate the underlying cause. Please temporarily switch back to the Islands theme and provide the following diagnostic details:

IDE Logs

• Collect logs via Help | Collect Logs and Diagnostics Data.
  These will help us inspect relevant exceptions and environment configuration.

CPU Snapshot

1. Go to Help | Diagnostic Tools | Start CPU Usage Profiling
2. Reproduce the slowdown for 20–30 seconds
3. Then invoke Help | Diagnostic Tools | Stop CPU Usage Profiling

Please start profiling only when the performance actually drops, and stop it right after you’re done.

You can submit these files in YouTrack restricting the attachment’s visibility to jetbrains-team or use our upload service and share the upload ID with us.

Thank you for helping us diagnose and resolve this issue!

Francesco Limberti, thank you for providing the logs. Turned out, there is a known performance issue with the Islands theme under investigation: IJPL-222923. We need your help, and we would appreciate if you could share more diagnostic information. Please switch to the Islands theme again and collect the CPU snapshot. Here's the instruction: 

1. Go to Help | Diagnostic Tools | Start CPU Usage Profiling
2. Reproduce the slowdown for 20–30 seconds
3. Then invoke Help | Diagnostic Tools | Stop CPU Usage Profiling

Please start profiling only when the performance actually drops, and stop it right after you’re done.

Once collected and uploaded, please share the upload ID with us! Thanks!

Ilnur Galimov Happy to help. I switch back to the Islands theme and collect the CPU snapshot following your instructions. 
Here is the sharing data: Upload id: 2025_12_15_AGyU3ELUVxbBWBBbeYWmKQ (file: IU-253.28294.334_user_15.12.2025_16.37.46.zip)

Hoping that this will be useful to you, I will try to describe how the problem manifests itself: The interface slows down immediately as soon as you change the theme, and every click anywhere in the IDE causes a slight delay, which makes for an unpleasant experience. It feels like using an old, slow computer.

Thanks Francesco Limberti, I’ll share this with our developers. Meanwhile, I'd suggest adding IJPL-222923 to your watch list so you won't miss any updates. Thanks again for your cooperation!

Both WebStorm and PyCharm is very lagging, especially during indexing, the whole UI basically non-responsive. IDE should prioritize user initial behavior rather than background indexing task

I, the IDE shouldn’t become unresponsive during indexing, so this behavior isn’t expected. To help us investigate, please share a full IDE log bundle collected after the lag in Help | Collect Logs and Diagnostic Data and a short performance snapshot taken while the freeze happens in Help | Diagnostic Tools | Start CPU Profiling. You can upload these using JetBrains Upload Service.

For the last few versions, RubyMine shows significant slowness on first startup. Many operations are affected, especially anything related to VCS, such as git fetch, git pull, and similar actions.

Restarting the IDE used to provide some improvement in performance, but with the latest version (2025.3) restarting no longer brings any benefit.

Even in previous versions, restarting was not always a reliable solution: typically the first restart would fix the issue, but not consistently. In several cases, after closing and reopening the IDE multiple times (3–4 times), the performance would degrade again, forcing me to keep restarting RubyMine until it became responsive.

With the current version, the slowness is so severe that I cannot work at all, even after disabling the Islands theme.

I am running on Windows 11, with the project located in WSL2.

I'm facing the same issue with PhpStorm 2025.3. It consumes almost all of my CPU, and this is after moving back to “Dark” theme and disabling metal.

Can you please help out? Thanks!

Here's the CPU profiling snapshot:

Upload id: 2025_12_17_a26HdLUmHAUgt8ScKfFRoz (file: PS-253.28294.345_angad_17.12.2025_19.33.04.zip)

Just chiming in. Upgraded to Webstorm 2025.3 and switched to the Island theme caused the UI to lag a log.
Switching back to Darcula theme and now it works without lag.

Adding to my previous comment: it looks like the “JavaScript & TypeScript” plugin is the likely culprit. CPU Usage reaches 100% every time I open a TS file, and goes back to normal when I close it.

@Ivan, could you please share a full IDE log bundle collected in Help | Collect Logs and Diagnostic Data? Please upload these using JetBrains Upload Service.

Ilnur Galimov Upload id: 2025_12_19_3haghkvB9EuEaQxyNUNTjZ (file: rubymine-logs-20251219-09543610038892742851112638.zip)

Francesco Limberti, I have a small update from the developers. They suggest trying the following workaround:

Please enable the Islands theme, but disable the Project Gradient.

You can do this in one of the following ways:

• Go to Settings | Appearance & Behavior | Appearance and disable Use project colors in main toolbar
• Right-click the main toolbar and unselect Show Project Gradient

Please let us know if this workaround improves the performance.