I’ve just killed and restarted Firefox, then duped my current set of tabs over to Chrome (in-house jukebox using websockets, a slideshare presentation, couple of open Google Docs spreadsheets, a Pivotal tracker session, a couple of tabs of a local development project, Google Plus, and this HN thread). Totalling up ‘Real mem’ in Activity Monitor shows Chrome 18 using 735.4mb (of which 33mb is Flash). Firefox 13 (beta release to be fair) is coming in at 450mb (of which 65mb is Flash).

The internal memory measurements (about:memory) come out as 835mb resident for Chrome, and 324mb (of ‘explicit’, whatever that is) for Firefox.

I’m not using any extensions in Chrome. In Firefox I’ve got installed Firebug, FireFontFamily, FireQuery, Lastpass, PDF.js and QuickJava.

Edit: oops, missed cloning a tab with a video in over to Chrome. That explains the disparity in Flash, and you could probably expect to increase Chrome’s real mem usage a little had I not closed it already…

This bug fix won't make much of a change right after starting Firefox, it just prevents memory from building up over time due to closed tabs. Additionally it's effective in nightly builds not beta, so 15.0a1 not 13.

Your comparison is useful overall, but not relevant to this change.

Realised that after I posted. Still, as you said this shows that Firefox has come a long way since the 4 days.

With Firebug installed, you most likely have JIT disabled http://antennasoft.net/robcee/2009/12/15/firebug-and-the-jit.... I would suggest you use a separate 'webdev' profile for such things (the inbuilt web console that is now in firefox is also getting there).

That was true in 2009 but was fixed in January 2010: https://bugzilla.mozilla.org/show_bug.cgi?id=534120#c52 (although it’s true that if you’re actively debugging scripts the JIT turns off - Firebug has the script panel off by default)

Incredible, I've been doing all my browsing for the past year with the script and console panels activated and had no idea that it was disabling the JIT for every page that I visited. Just turned them off, and I can't believe how accustomed I'd become to sluggish webpages. Thanks for the link!

Thanks, that's great to know, time to give the latest FF another go.

If you haven’t done so already, it’s probably worth killing your old Firefox profile and starting completely anew.

> How are you current Firefox users finding the RAM usage, especially compared to Chrome?

I'm fairly sure that multiple studies have shown that Chrome uses more RAM than Firefox. But that's not what's important - all that matters is whether the browser appears snappy to the user. That's much more so the case with Chrome than it is with Firefox.

That's correct. Snappiness is what really is important. Mozilla conduct a parallel project called Snappy to improve that specific metric.

Note that Memory consumption is somewhat related to Snappiness: if it is too high, the program will slow down (paging, longer garbage collecting pauses, ...) and feel less snappy.

Assuming the system’s not paging.

I don't think memory's the bottleneck on most modern systems, so it seems like Google made the right choice by allowing greater memory usage in return for better end-user performance.

You're right in that Google's made excellent engineering tradeoffs to keep Chrome snappy, but note that memory is, sort of, the bottleneck on modern systems. Specifically, the channel between memory and the CPU:

http://en.wikipedia.org/wiki/Von_Neumann_architecture#Von_Ne...

Memory paging is the major bottleneck if you're on a Macbook Pro running Lion with no SSD.

I don't know much about Macs, but does the OS use a lot of memory or something? Or does it have to do with the hardware?

I'm not sure exactly why this happens, but it does use a lot more memory than you'd expect. Right now, I have 13 Chrome tabs open, Mail.app, a Terminal session, Colloquy, and TextWrangler running but with no documents, but it has 1.14 GB wired (as in, can't swap) and 1.66 GB active. That's a total of 2.80 GB memory in use.

But also, it takes a while to swap (upon which it beachballs all over the place), and it's not very intelligent about when to swap.

It's a 2.00 GHz quad-core machine, so I have plenty of CPU power. It's just that when I get working on more than one or two things at once, switching between them swaps everything to heck.

Informed users know that this 'memory usage' is caching, not leaking and that you can limit it if you really want.

BTW, History / Recently Closed Tabs is one of my favorite FF (only) features.

"Recently Closed Windows" is even better, for those times when you accidentally manage to close your main browser window with 200 open tabs, expecting Firefox to restore them the next time you start the browser, without realizing that you have a dinky little popup window left over somewhere.

But also note that Opera's had a Recently Closed Tabs dialog for as long as I can remember.

> BTW, History / Recently Closed Tabs is one of my favorite FF (only) features.

Chrome also has the "Recently Closed" list.

The list under 'History'? That's not the same, just history.

No. Open a new tab and on the bottom right look at 'Recently Closed.'

It's been in Chrome for awhile.

Oh, I see. Thank you!

Since months (I would say Firefox 7), Firefox is better than Chrome when used with a lot of tabs.

Chrome uses more memory, but for good reason. I think they load more stuff in RAM so the browser works faster, and there's also the sandbox security feature, which makes it so tabs don't share memory, so that must add quite a bit, too. That being said, I wouldn't mind if the Chrome team worked on optimizing RAM usage as well, if they aren't doing it already.

What is the basis of your belief that their increased memory usage is because they "load more stuff in RAM so the browser works faster"? In my experience working on MemShrink, almost all of the things we have fixed are the browser using more memory for no particularly good reason, and I would be surprised if this wasn't also the case in Chrome. You are right that sandboxing does incur some overhead, but I'm not sure how much. But I agree with your overall point, that memory usage is by itself is not as important as overall system performance.