I installed xubuntu desktop on top of ubuntu 12.04. The usage of RAM and CPU is in general lower than in ubuntu. But when it comes to some serious computations I did not see much of a difference between the two. For example, I ran a Matlab program that took 99 seconds to run on ubuntu and 98 seconds on xubuntu. Then I ran Geekbench benchmarking and the overall scores ubuntu and xubuntu are 2996 and 2997, respectively. My laptop is a 4 year old dell 1535. Would things run faster on a clean install of xubuntu?
This is an issue that I looked into pretty seriously because I had an older laptop that was not running very smoothly at all. It took forever for programs to open and execute various tasks, and get slower as I used it. I experimented between Xubuntu and Ubuntu, and kept track of times to see the difference.
The technical answer is, yes, Xubuntu is faster than regular Ubuntu.
But, the more accurate answer is, no, probably not in any way that will make a difference to you.
If you just opened up Xubuntu and Ubuntu on two identical computers and had them sit there doing nothing, you would see that Xubuntu's Xfce interface was taking up less RAM than Ubuntu's Gnome or Unity interface.
But, so what? You don't just run computers to have them sit there. And here's where the rubber hits the road.
With respect @UriHerrera, Xubuntu isn't just Xcfe, it's also a whole suite of application options to handle most tasks you want to do. For example, if you wanted to do word processing, on Xubuntu it has Abiword preinstalled. On regular Ubuntu, you're offered LibreOffice Writer by default.
Abiword may take less resources, but you pay for that with less features. And while I probably don't use 90% of the features available in Writer, the difference was noticable enough that I found I would rather use Writer.
Now, even though underneath Writer Xubuntu's Xcfe interface is using less resources than Ubuntu's Gnome or Unity, the question you're coming down to is this: Is it using enough less to make a difference in how fast LibreOffice Writer runs?
The answer is, no, not really. LibreOffice uses so much resource on its own that it quickly eats up any savings in using Xcfe. For all intents and purposes, when running something like LibreOffice on Xubuntu, the difference is so negligible as to not matter.
So, if you're content to stay within the suite of applications offered by Xubuntu, then you might see some difference.
If, however, your hope is to run more or less the same programs as you would with Gnome or Unity but are hoping to get a noticeable performance boost, then there is no meaningful difference. By "meaningful difference", I mean a difference in how fast programs open or execute tasks to a degree that a human can tell the difference. I don't know about you, but saving .03 seconds if it takes a minute and a half to open a program doesn't mean anything to me.
In the end, I found that buying more RAM for my laptop - going from 512MB to 1GB - made such a significant impact that I forgot about trying to squeeze tiny amounts of performance by switching desktop environments.
So the question about which is faster, Xubuntu or Ubuntu, comes down to this: what applications do you want to use? Go with the whole Xubuntu suite, then you might notice a performance boost. But as soon as you start using bigger applications, the interface savings will become moot.
The Kernel is the same, the underlying system is the same, the tools are the same, the desktop is different. it's the same Operating System it's just using different Desktop Environment.
Probably yes. Regular Ubuntu brings Unity and a lot of more programs that are kept executing in memory, while Xubuntu brings less of those.
If you want a really fast and less memory consuming, you can try download Ubuntu server and install only what you need, or even use a WM likde Openbox instead of a DE.
If you are doing the same 1 billion multiply operations, without accessing windows or any other operating system function, and nothing else is going on in the background, it shouldn't really matter what operating system or desktop environment you are using Ubuntu, Red Hat, Windows. The hardware is the constraint. If whatever operating system is bringing the program into memory and then letting the processor or processors do their best your hardware will mostly determine the speed (assuming all of the operating systems handle the multiple processors, hyperthreading, and so on).
When compiled with a better compiler, or compiled with more optimization, you may not be performing quite the same number of operations, however. Ubuntu, Xubuntu, Red Had, probably are using about the same compiler. It may make a difference how matlab is compiled between Ubuntu/Debian and Windows, however.
When you get into doing reads and writes to disk you shouldn't necessarily expect a benchmark to work the same on Windows, BSD, or Linux, but should probably expect the Linux numbers to be about the same, including Ubuntu and Xubuntu, (but the kernel's will be configured differently and that may make a difference).
If you are putting someone at the desktop and have taught them how to perform some task, Ubuntu and Xubuntu will use different resources when they perform them later, Xubuntu probably fewer resources. The individual may take more or less time to perform the task with either Ubuntu or Xubuntu. In this case it makes all the difference what you decide to measure.
I came here looking for a technical answer... I didn't found that.. Im looking into this for an ubuntu server install on a pretty low resources box..
So here is a better technical answer with resources comparison: http://mylinuxexplore.blogspot.com/2012/10/ubuntu-1210-vs-kubuntu-1210-vs-xubuntu.html
hope this helps someone..