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

Nobody · Unread post by **Nobody** » 16 Dec 2025, 14:17

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.

Unread post by **Duke** » 16 Dec 2025, 21:08

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

Unread post by **Duke** » 16 Dec 2025, 21:17

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 903 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 903 times

Unread post by **Duke** » 18 Dec 2025, 20:48

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 · Unread post by **mauro** » 19 Dec 2025, 11:10

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.

Unread post by **Duke** » 19 Dec 2025, 22:49

mauro wrote: ↑19 Dec 2025, 11:10 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 · Unread post by **mauro** » 20 Dec 2025, 09:41

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?

YouTube · Unread post by **the_r3dacted** » 20 Dec 2025, 11:22

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 · Unread post by **mauro** » 20 Dec 2025, 12:50

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.

Unread post by **Duke** » 20 Dec 2025, 15:08

mauro wrote: ↑20 Dec 2025, 09:41 Switching allocators can affect **performance consistency**, **debugging tools**, and **cross-platform compatibility**.

That means a hard testing is needed.

Unread post by **Duke** » 20 Dec 2025, 19:15

the_r3dacted wrote: ↑20 Dec 2025, 11:22 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

Unread post by **Duke** » 22 Dec 2025, 22:57

Duke wrote: ↑16 Dec 2025, 21:17 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 242 times

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

Similar bug reported here:
https://github.com/Eclipse-Community/r3dfox/issues/95

Eclipse Community