r3dfox, a modern Firefox based web browser for Windows Vista, 7, and 8!

[Nobody]

Is it what is reported by this site ? :

Yes

If so, then in about:config check the value of the general.useragent.override key.

The value is Mozilla/5.0 (Windows NT 6.1; rv:131.0) Gecko/20100101 Firefox/131.0
I adapted it.

[Duke]

For the record, to avoid fingerprinting the best user agent, as of today, should be:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0

[Duke]

I have a strange bug/annoyance with R3dfox 146 when I right click on the page back/page forward arrows at the top left corner.
When I slowly hover the pages history with my mouse several lines keep being highlighted at the same time:

R3dfox146-PagesHistory.png (12.13 KiB) Viewed 386 times

This doesn't happen with Firefox ESR and LibreWolf.
I'm using the dark theme + the dark mode + Eclipse Purple.

R3dfox146-Visual.png (30.46 KiB) Viewed 386 times

[Duke]

Firefox 146.0.1 has been released with several fixes:
https://www.firefox.com/en-US/firefox/146.0.1/releasenotes/

as well as some security fixes:
https://www.mozilla.org/en-US/security/advisories/mfsa2025-98/

[mauro]

Is this worth it? I saw another guy did this in Firefox, I don't know if it would be worth doing it for you too

Disabled the integrated memory allocator jemalloc and adopted mimalloc.

[Duke]

Is this worth it? I saw another guy did this in Firefox, I don't know if it would be worth doing it for you too
Disabled the integrated memory allocator jemalloc and adopted mimalloc.

What are you talking about ?

[mauro]

simply changing jemalloc to mimalloc seems like mimalloc consumes less resources and is faster

**Quick Answer:** Firefox primarily uses **jemalloc** as its memory allocator because it improves performance, reduces fragmentation, and handles multithreaded workloads efficiently. While **mimalloc** (developed by Microsoft) is another modern allocator with strong performance, Firefox has not adopted it as its default.

---

## Firefox and Memory Allocators

### What is a Memory Allocator?
- A memory allocator manages how applications request and release memory at runtime.
- It affects **speed**, **fragmentation**, and **overall stability** of programs.
- Common allocators: **jemalloc**, **mimalloc**, **tcmalloc**, and system defaults like `malloc`.

---

### Firefox and jemalloc
- **jemalloc** was introduced in **Firefox 3** to replace the standard `malloc`.
- It was designed by **Jason Evans** for FreeBSD and later adopted by Firefox.
- **Key benefits for Firefox**:
- **Reduced fragmentation**: Keeps memory usage more compact, lowering RAM consumption.
- **Better multithreading support**: Handles concurrent allocations efficiently.
- **Performance improvements**: Faster allocation/deallocation compared to system `malloc`.
- **Predictable scaling**: Works well under heavy workloads like rendering complex web pages.

---

### Mimalloc (Microsoft)
- **mimalloc** is a newer allocator created by Microsoft Research.
- It is **compact, fast, and consistent** across benchmarks.
- Outperforms or matches jemalloc, tcmalloc, and others in many scenarios.
- However, Firefox has **not switched** to mimalloc as its default allocator.
- Mimalloc is more commonly used in Microsoft projects and experimental builds.

---

## Comparison Table

Feature	jemalloc (Firefox default)	mimalloc (Microsoft)
**Adoption**	Widely used in Firefox, FreeBSD, Rust	Used in Microsoft projects, experimental adoption
**Performance**	Strong, optimized for multithreading	Very strong, often faster in benchmarks
**Fragmentation**	Low, stable under heavy loads	Very low, compact memory footprint
**Maturity**	Older, battle-tested	Newer, still gaining adoption
**Integration**	Deeply integrated into Firefox	Not default in Firefox

---

## Trade-offs and Considerations
- **jemalloc** is deeply integrated into Firefox’s architecture, making it reliable and stable for millions of users.
- **mimalloc** shows promising results but would require extensive testing and integration work before replacing jemalloc in Firefox.
- Switching allocators can affect **performance consistency**, **debugging tools**, and **cross-platform compatibility**.

---

In summary: **Firefox relies on jemalloc for its proven stability and performance. Mimalloc is a strong alternative allocator, but it’s not currently used as Firefox’s default.**

Would you like me to also explain **how jemalloc works internally** (its algorithms like arenas, bins, and slabs) so you can see why Firefox chose it?

[the_r3dacted]

Not sure when I will get around to working on 146.0.1. Probably just a basic rebase and build, but then I'd want to also fix the menu issue, 140, and 128 at the same time, and I don't feel like all that right now in the middle of another project.

If you tell me how to do it, I will try changing jemalloc to mimalloc and see what happens, but you must tell me how to do it.

[mauro]

I don't know but AI assistants can help with this task, look at the copilot's answer on how to do it

https://copilot.microsoft.com/shares/TfqVqZh68fYsB3XP3Un38

If there are errors, showing the copilot an error, he will advise what could have gone wrong, etc.

[Duke]

Switching allocators can affect **performance consistency**, **debugging tools**, and **cross-platform compatibility**.

That means a hard testing is needed.

[Duke]

Not sure when I will get around to working on 146.0.1. Probably just a basic rebase and build, but then I'd want to also fix the menu issue, 140, and 128 at the same time, and I don't feel like all that right now in the middle of another project.

I understand you are busy with another project but FYI e3kskoy7wqk has just released a 146.0.1 version so maybe that's not too much work to do for you for R3dfox

https://github.com/e3kskoy7wqk/Firefox-for-windows-7/releases/tag/146.0.1