Turbopack consuming large amounts of RAM on macOS in dev mode

[b-bot]

Link to the code that reproduces this issue

https://gist.github.com/b-bot/787cbc3b6c39bc4f313c312d6beaa76b

To Reproduce

This is quite difficult as I am not able to share my project code and it might be to do with dependancies. However I have gone through everything mentioned in related issues and nothing seems to resolve it.

I have shared my package.json of everything I have installed along with the relevant trace files and next config. Something to note is that this app is in a Turbo monorepo using pnpm.

Essentially I was experiencing RAM usage of 8-10GB when using next dev without the --turbo flag. This was accompanied by extremely slow page, api and component rendering times of over a minute.

I moved to turbopack which has been phenomenal for page loading speed and HMR, my dev server is finally useable again. Only issue now is that despite RAM usage of the next-server subsiding to around 6GB (still seems a little high as my app is only medium complexity), my VS Code RAM usage slowly balloons to over 30GB (my machine only has 16GB).

Eventually I get the dreaded "Your system has run out of application memory" macOS window reporting the high RAM usage of VS Code.

Current vs. Expected behavior

Current: System uses high RAM for VS Code when using turbopack.
Expected: VS Code RAM usage stays the same and this is reported in next-server instead and reduced significantly.

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.2.0: Fri Dec  6 19:01:59 PST 2024; root:xnu-11215.61.5~2/RELEASE_ARM64_T6000
  Available memory (MB): 16384
  Available CPU cores: 10
Binaries:
  Node: 23.6.0
  npm: 10.9.2
  Yarn: 1.22.19
  pnpm: 9.15.4
Relevant Packages:
  next: 15.2.0-canary.18 // Latest available version is detected (15.2.0-canary.18).
  eslint-config-next: 15.1.5
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.7.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Turbopack

Which stage(s) are affected? (Select all that apply)

next dev (local)

Additional context

I am using the 15.2.0-canary.18 when tracing the results however I have had this issue for a few months now outside of turbopack. It seems that turbopack is just masking the real problem at the expense of VS Code memory usage.

Also aware that there is a central place for issues like this such as #48748 but this seems more directly related to Turbopack and slightly different in that it affects VS Code RAM usage while performance is substantially better.

[github-actions]

We could not detect a valid reproduction link. Make sure to follow the bug report template carefully.

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Useful Resources

• How to Contribute to Open Source (Next.js)
• How to create a Minimal, Complete, and Verifiable example
• Reporting a Next.js bug
• Next.js Triaging issues