Some Numbers About LXQt for Those Who Are Curious

After the initial release of LXQt, I found that there is a FAQ. How’s the memory usage? Will it become a bloated memory hog because of Qt? Here are some numbers for you.
My test environment is the latest Debian stable installed in VirtualBox with 512 MB of RAM and 1 CPU core assigned. After cold boot, the memory usage is as follows.

  • Plain Openbox only: 58 MB
  • XFCE: 89 MB (with default configuration of Debian. This value will increase after xfce is ported to gtk+ 3)
  • LXDE (gtk+ 2 version): 78 MB (add 20 MB to openbox)
  • LXQt: 95 MB (add 37 MB to openbox, still has some room for optimization)

The screen resolution is 1280 x 1024. So a wallpaper roughly used 1280x1024x4 bytes = 5MB of RAM. If you don’t set a wallpaper, this number can be lower. Besides, this is a virtual machine so some special modules for vbox are loaded. I turned off printer service and network-manager applet since they’re not used.

Yes, the memory usage slightly increased, but the difference is really negligible. Moreover, LXQt has more features, such as a better program launcher and new power management stuff.

Apparently the gtk+ 2 version uses less memory, but we cannot use gtk+ 2 forever. It’s not a secret that gtk+ 3 is not a memory saver. So, I’d say Qt is really not that bad.

Why yet another DE? Why can’t you do something more innovative? I think the answer for this FAQ is simple.

  • Nowadays everything goes mobile and touch, but we still saw unmet need for a classic desktop environment. Otherwise, Windows xp should have been killed years ago and Windows 8 should have high market share now.
  • In the history of free software, we see forking everyday, but (successful) merging rarely happened. We want to prove that it actually works. People can focus on what they can share with each other, not how they are different.

The following is my personal opinion (not on behalf of other LXQt developers)
Seriously, if a 17 MB memory usage increment can buy us faster development, more active developers [Figure 1], more contributors, and a healthier upstream community, that’s definitely worth it. When I say healthier, I mean those who do not hold a “Follow our way, or go away!” attitude. This is just as important as other technical considerations when you choose a toolkit.
Many people like to argue that Qt is not C++ since it requires a pre-processor. Did anyone tell you that Gtk+ actually uses a preprocessor, too? Check the manpage of “glib-genmarshal” please. Without this pre-processor to generate some code for you, it will be awfully difficult to add signals to your GObjects. That’s not C language, right?
It does not really matter for users what toolkit you’re using given the final result works. Let’s save some time not arguing which is better and focus on what we can do with them. 🙂

Figure 1. A screenshot from Google Trend

26 responses to “Some Numbers About LXQt for Those Who Are Curious”

  1. “…but we still saw unmet need for a classic desktop environment.” Yeah, a laptop or a desktop computer is not a smartphone or a tablet. Classic desktop environments are still the best solution for desktop users. Imagine if they decided that a car tire should not be round anymore, and wanted a different shape instead?! Certain things are better off the way they have always been.

  2. I really like the Razor-Qt and LXDE merge and i agree that by working together, both can help each other and advance more than ever.

    I am not a dev, but i will do my best to help with testing and spanish-focused content and promotion 😀

  3. “It does not really matter for users what toolkit you’re using given the final result works”
    Definitely. Users in general don’t even know or think about desktop environments at all, for many Ubuntu is just everything that shows up after boot. Try to explain a Windows-native the concept of more than one environment … And til now it works flawless – great work!

  4. I do like the idea of a merge, and it really is looking nice.

    However, the whole reason I switched to LXDE in the first place is that the panel was bloody awesome. I had also tried Razor-QT, but did not like the panel, so I never used it (though I did watch it, and check it out often to see if it was “fixed”). Now with LXQT it seems you are using the Razor-QT’s panel. I can understand the reasoning, as why port when you have a working one, but it just doesn’t compare to LXPanel. I just hope that the panel gets some LXLove.

    That being said, I will continue to follow LXXX to wherever it may go, as it is still leagues above others IMO. My next install I will go with LXQT, though likely with the GTK LXPanel.

  5. I wonder whether the distinction between LXQT and XFCE will make sense in the future. According to the numbers above, LXQT now uses more resources than the current version of XFCE. As far as I know, XFCE will also move to qt as a toolkit (right?). So wouldn’t it may sense to join resources even more and merge LXQT and (qt-based) XFCE? If not, what fundamental differences between the projects justify to hold them apart?

  6. Hey guys I notice the wifi applet is not on the bar, I saw some people discussing about it and some solutions that are “emergencial” and fallback to the old fashion icons, will they release a bugfix for that? thanks guys!

  7. i don’t mind the increase in memory usage too much, but you guys are going to continue working on reducing it and refining LXQt, right? (after LXQt stabilizes enough since it just had it’s first public release ofc)

    Kinda got the “I don’t fucking care about the memory footprint all that much anymore as long as the project is active” feeling from this post.

    I don’t think I’ll be using LXQt if the memory footprint continues to rise overtime.

  8. First, I want to answer a claim in another comment: no, XFCE is not switching to Qt, they are going GTK3.
    The other thing I wanted to point out is, while it is still a relatively small footprint, I wouldn’t call the increase “negligible”, as it almost doubles if you take out the window manager, since the project doesn’t work on that area. It goes from 20MB to 37MB, a 94% increase. I do consider it reasonable and actually see Qt as a better toolkit in most aspects, but “negligible” would be going from 20MB to ~21MB, a mere 5%.

  9. Sorry, 85%, not 94%. I made the calculations on the top of my head and did them wrong. Still, same point.

  10. Well, classic desktop is optimized for regular working with keyboard and pointer use for handling with apps. Some desktop environments tend to nonlimit expanding by adding features witch are not generally demanded by users. In GTK is very clear that sweeping up and polishing the code does not provide less burden for a system where is used. If LXQt developers succeed with keeping desktop lightweight and speedy, merger of LXDE and Razor-Qt will make a sense.

  11. I only have one question:

    Where can i download the theme presented in the images at

    I suppose it’s called Oxygen or something like that since it looks like KDE’s Oxygen but i can’t find where to download it… It’s an amazing theme!!!

  12. I don’t care much about memory footprint. I like LXDE for its classical look&feel, and for minimalistic approach in design.
    Development resources are always limited. If I could judge here, I would definitely prefer to spend them on stability rather then footprint improvements.
    Interesting to know the numbers here – how many LXDE users really consider footprint an issue. How about arranging a pool?

  13. My apologies, XFCE will indeed move to GTK3, albeit there has been some discussion about switching to qt… Let’s see how XFCE/GTK3’s memory footprint will compare with that of LXQT… Anyway, I am very happy with LXDE right now and will probably switch to LXQT in the future. Thanks for the good work!

  14. MATE uses slightly more memory than XFCE which means that LXQt is comparable to MATE’s memory footprint. I’d much rather use a mature and stable DE like MATE over LXQt if I had to choose between the two.

    LXQt has lost its niche and at the moment it’s just a middle-weight Qt desktop for those that don’t want to use KDE.

  15. Dmitry, I rather consider most LXDE users choose it because of memory footprint. That’s one of the most easily measurable parts of being “lightweight”, and that’s the main promise. A nice, usable DE that is *lightweight*. As for minimalistic/classic look and feel, you can achieve that with other options, too. For example, with XFCE. IMO, the main strenght of LXDE is being both lightweight and user friendly. It’s something I can install in my mother’s computer, which is a bit on the older side, and don’t worry it will hog resources. It’s still a valid option, but a nicely configured XFCE might be friendlier, and is now slightly lighter. So, it finally comes to this: if I can get it to use just one of the major toolkits, that’s what will make the choice in the end, as not having to load both will make up for any difference in size. As she uses mostly Firefox, the best option for that machine is to try to restrict to GTK.

    Anonymous, I vastly expect XFCE will be heavier when the port to GTK3 is complete, but I don’t think that’s really relevant to the point of collaboration, is it? They can still collaborate in the same way most DEs do, which is by adhering to standards, but code sharing is more likely between them and KDE than between them and XFCE.

  16. I tried XFCE few years ago, and did not like it then (switched back to Gnome-2). Maybe it’s worth trying it again, I don’t know. XUbuntu did not have x64 builds for some time (now they do).
    I like Openbox, and have written quite a few custom lines in its config. I don’t want to switch to something else now.
    I understand your position, Oppen. And of course I don’t mind LXDE being also lightweight – it’s a good thing, anyway. I just wonder how many LXDE users really chose it mainly for its footprint. There are enough other reasons to like it 🙂

  17. I really digged LXDE but enjoyed Qt a little bit more. I wanted a distro a little easier after being an Arch Linux user for years, I went back to my first distro Kubuntu. I was using Kubuntu from the days of 9.04 but after a few more years KDE4 has become more stable and easier to use.

    If LXQt keeps going the way it is going, I will make the full switch to Lubuntu. For right now, i will continue to use Kubuntu until LXQt gets a little mature. The only issue with LXQt thus far is PCManFM-qt not allowing me to delete files from my USB Pen/Thumbdrive.

    So, I have installed SpaceFM in PCManFM-qt place for now.. I only see SpaceFM using 35MB.. which I think is not too bad.

    Continue the good work 🙂

  18. I’m digging it. I think Qt was the right way to go. I’m sure you’ll reign in the memory usage a bit by the time this is finished and the tradeoff is definitely worth it. Just don’t start getting big heads like those folks over at GNOME, haha.

  19. Memory usage isn’t the sole benchmark for “lightweight”, CPU use and disk accesses are very important too. (of course, the measurement of RAM consumed at a fresh empty desktop is simplistic, it’s nice to have but doesn’t tell what happens next)

    This is where LXDE GTK is very quick, and especially the file manager (I still have version 1.1.2 installed), I think you all know what I mean, you just don’t have to wait on it to do mundane every day stuff.
    I had it installed in the 0.9.x days on a Pentium II 233, 4GB hard drive (must be slow enough) and 96MB RAM, it was stil quick. Old school “do one thing at a time” if you don’t want to overload the memory but it did everything except web browsing (and divx/xvid decoding, for which that CPU was too slow).

  20. another issue besides the one I commented on before. The audio applet isn’t very useful if you are running more than 2 audio cards nor is it’s recommended mixer. Has issues with Mute.. Mutes my Soundcard audio but will not unmute and leave my HDMI sound alone. Very annoying since I love my Logitech G15 keyboard.

    For now removed the mixer applet and used Kmix instead.

  21. @Oppen, your calculations are off because you are just looking at how much more these options take than openbox. If you are computing a percentage increase, then you need to know how much openbox takes (for example, if openbox takes 20MB, then the percentage increase is half of what you calcuated because then the comparison is 40MB -> 57MB not 20 -> 37)

  22. David, I’m trying to measure what LXQt takes, not LXQt+WM. The project doesn’t provide a WM, and the WM is switchable while still considering it LXQt. For example, if you are going to use Wayland, Openbox is out of the question, you’ll have to go with KWin or something similar. Which is a great pointer to: it would be interesting to know how much memory a minimal build of KWin takes.
    If the point is to check the percentual increase for the whole system, then I’d have to know the workflow of the particular person, and that would be a never ending story.