High memory baseline

[brielov]

This has probably been asked before, but I was testing both rolldown-vite and the new Oxc React plugin using the exact same project structure — just Tailwind v4 in an otherwise empty project — and comparing their dev server memory usage (not build time).

On my machine, the rolldown-vite setup with the Oxc plugin used around 190MB of RAM, while the same project using regular Vite with the React SWC plugin used only 50–60MB.

I know this is still a preview, but is this memory difference a known issue? I would have expected the numbers to flip for larger projects, but I was surprised by the high baseline usage — especially considering Rust tooling is generally praised for efficiency.

Would love to hear if anyone has insights or context on this.

That said, I’m super hyped about this whole Rust rewrite — it’s incredibly exciting to see the ecosystem evolving like this. Amazing work so far, and huge props to everyone involved.

[sapphi-red]

Hmm, would you create a repo that I can try it out? I'm not sure what's happening there.

Also how did you measure the RAM usage?

[brielov]

Here's a simple repository I was testing: https://github.com/brielov/vite-memory-example

The biggest difference is on Linux x86_64. I tested it on an M4 Mac mini, and the difference is less steep but still noticeable. Classic Vite uses 70MB, while rolldown-vite uses around 130MB.

I'm using the built-in system monitor for Mac and "resources" for Linux/Gnome. I know this might not be the most accurate way to measure this, but I'm curious.

[sapphi-red]

Hmm, this is weird.
If I use a local rolldown build, the max memory usage is ~168MB. On the other hand, if I use the prebuilt one (@rolldown/core-linux-arm64-gnu), the max memory usage is ~252MB. (Normal Vite is ~211MB).
The built binary is different, so there's probably something wrong with the build config in rolldown.

[sapphi-red]

Made an issue here for now: rolldown/rolldown#5176