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I noticed that when I use default Ubuntu's Unity, everything scrolls fast and smooth. By "everything" I mean web-browsers and vim in terminal when I browse source code.

When I use xmonad it seems to be much slower. I load xmonad as a separated xsession. Maybe I should add some command to my startup script in order to enable video acceleration?

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Yes, I have this exact problem too. Please, do me a favour. Install htop (sudo apt-get install htop) and tell me the average CPU usage of X11. When my experience degrades I start seeing the X11 process start to eat up around 50% of my CPU usage. High X11 CPU usage seems to be a symptom of this problem for me and I would love to get to the bottom of the problem with you so that both of us have a better experience. – Robert Massaioli Feb 16 '13 at 10:42
@RobertMassaioli, good, I'm happy to cooperate in this. As you suggested, I installed htop and noticed that the process user/bin/X (I guess it's X11) is consuming around 15-25% CPU when I do scrolling in vim. ( I will try to do the same in unity and compare the difference. – evfwcqcg Feb 16 '13 at 11:54
In Unity, average CPU usage of usr/bin/X is about 30-40% when I do scrolling in vim. And 3-5% for both, Xmonad and Unity, when computer in idle. – evfwcqcg Feb 16 '13 at 12:09
Well that is unexpected. So you are saying that you roughly see the same CPU usage for X in Unity as you do in XMonad. That is a bummer. I don't think that I have the same results. I think though that X11 is using up too much CPU on your machine. I am led to believe that X's CPU usage is supposed to hover around the 5% - 20% mark when it is working properly (what you are seeing in idle). – Robert Massaioli Feb 17 '13 at 22:28
See this page suggests that it should only hover around 5% at all times: – Robert Massaioli Feb 17 '13 at 22:29

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