I know this seems like a duplicate of some other people posting, but This really bugs me. Last week I switched back to windows XP. After XP starts I even sit and wait because I am so used to waiting, but then everything has loaded. KDE 4.3..x was somewhat better than 4.2, and later NVidia drivers made things a bit better. KDE is really slow for me with or without compositing. I am not sure whether its Kubuntu, my NVidia drivers, KDE itself, QT or my hardware:

My system specs:
Nvidia nforce 4
AMD athlon x2 4200 cpu
1 GB DDR Ram
NVidia GeForce LE 7300

The problem is the impact on usability. KRunner takes too long to find things. I have to type and wait for the thing I am searching for to show up. Dolphin takes ~10 seconds to load, kate takes ~10 seconds to load, and it's only a text editor. I am used to XP where everything pops up almost instantly.

The slowness extends to desktop effects as well. Every effect has what seems to be some sort of pre-loading issue. If i use cube for the first time its very laggy and ugly, but using it after that is fast. The same thing goes for almost all the effects.

Before KDE4 was released there was news that It was supposed to be faster than KDE3 but I can remember KDE3 being extremely brisk, and KDE 4 in comparison is a slug.

What are your opinions on the speed of KDE4? Are there ways to improve it? Some people advertise that their systems are fast with KDE4, am I missing something?

your video card does not work. try changing drivers and settings. there are no good nvidia drivers on linux. onboard nvidia graphics make even more trouble

nepomuk / strigi are digging up your hard drive. disable them in system settings - desktop search

you have the desktop wallpaper bug. change desktop background from wallpaper to plain color (use the picture frame plasmoid to pimp your desktop instead)

ram 1 G is ok i think

go to sysguard and see

how much ram is used ? is there too little memory used for cache ? does you computer use swap ?

what processes eat up cpu when you use the computer ? if its x or plasma then its sure a graphics problem

KDE4 was unbearable slow on my brother's computer. Plasma felt sluggish, it took a couple of seconds for Kickoff to show up and the same for e.g. KRunner. The computer is quite old but runs Gnome fine.

I tried to run Plasma and KRunner with the raster graphics system, and suddenly everything flies! The ZUI is even faster than on my desktop computer (which isn't exactly the newest model either).
The strange thing is that it remained quite fast, even after a reboot. I didn't have enough time to investigate it further, though.

To run Plasma with raster, do the following:

Code: Select all

kquitapp plasma-desktop
plasma-desktop --graphicssystem raster

(For earlier KDE version before 4.3, drop the -desktop suffix).

Note that this has it disadvantages, for example in memory usage.

Output for top:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

4965 myuser 20 0 864m 62m 20m S 5 6.4 0:43.15 plasma-desktop
4958 myuser 20 0 512m 38m 17m S 3 3.9 0:37.45 kwin
5241 myuser 20 0 576m 101m 21m S 2 10.2 0:33.52 firefox-3.5
4806 root 20 0 295m 85m 4304 S 2 8.7 1:00.39 Xorg
8583 myuser 20 0 264m 30m 14m R 2 3.1 0:16.43 ksysguard
9320 myuser 20 0 400m 40m 16m S 2 4.1 0:01.56 konsole
8585 myuser 20 0 11580 1648 888 S 1 0.2 0:02.82 ksysguardd
2871 chipcard 20 0 27460 1080 700 S 1 0.1 0:07.47 chipcardd4

Changed my wallpaper to color only: seems to have no effect on my problems. As you can see neither strigi or nepomuk are running. I tried the raster thing and it doesn't seem to make a visible difference.

So in conclusion... this looks to me like a graphics driver issue. I am running the Nvidia beta driver 190.18 because i had some strange crashes with the 185 versions, and it was much slower. This is naturally extremely frustrating. Kwin and Xorg spike in cpu usage when I move windows so that is an indication to me. I have tried changing some random settings in the xorg.conf file based on a forum post by another nvidia kde user but this hasnt helped either.

KDE is like lightning on here (I have even considered it to be faster than Gnome and I'm sure Dolphin fired up faster than the file manager on XFCE! lol)... maybe it's your graphics drivers or something. I have always found nvidia drivers to be very good, and ATi drivers to be... ok

I have an Nvidia geforce in here and my pc is of average specifications.

It's very odd you're having this problem with nvidia but I guess it's down to the precise hardware - although I am surprised a more stable and faster driver doesn't exist for it.


EDIT -- Have you turned off Kwin compositing?

i have a box with intel graphics which actually sometimes feels faster with composite on. and i dont think its illusion (it feels faster in places where there is no effect too)

Sluggish KDE behavior is problem of video drivers. There was a lot of problems with Intel chips but they slowly getting things right. There is a lot of problem with NVidia cards due to kernel bugs with PAT and MTRR handling. If you doubt your prcessors supports PAT right way, say "nopat" in kernel command line.

Generally speaking, KDE is big and slow but 4.3 is much faster then previous releases. I think KDE guys considering speedup and lower memory footprint.

The short answer, I think is, "depends on the hardware, and the drivers". In my experience, KDE3 runs great on everything.

Now, when I was running Kubuntu, I upgraded from KDE4.2 to 4.3, and I noticed a marked decline in performance. Then I upgraded from Jaunty to Karmic Beta, and I noticed a marked improvement in performance, but the support for Mplayer was lousy with no w32win codecs, and no full-screen mode. So I switched from Kubuntu to Debian Lenny with KDE3, and now it's all good.

KDE4 will get there eventually, and they're doing a great job. Maybe if I knew more about drivers I could get better performance out of KDE4, but for now, even if it's my fault, and not KDE4's, it's KDE4 that has to go.

Hans wrote:KDE4 was unbearable slow on my brother's computer. Plasma felt sluggish, it took a couple of seconds for Kickoff to show up and the same for e.g. KRunner. The computer is quite old but runs Gnome fine.

I tried to run Plasma and KRunner with the raster graphics system, and suddenly everything flies! The ZUI is even faster than on my desktop computer (which isn't exactly the newest model either).
The strange thing is that it remained quite fast, even after a reboot. I didn't have enough time to investigate it further, though.

To run Plasma with raster, do the following:

Code: Select all

kquitapp plasma-desktop
plasma-desktop --graphicssystem raster

(For earlier KDE version before 4.3, drop the -desktop suffix).

Note that this has it disadvantages, for example in memory usage.

Interesting tip but what does it do exactly (ie. what is the default graphics system and how is raster different? ) and how to make it the default for every session?

The only way to make raster the autostart backend for Plasma is to alter the Plasma Desktop autostart desktop file. This is likely in /usr/share/autostart.

Slow? Well, not really. Not to me, at least.

I've run it on one desktop computer (assembled out of spares) where only KDE would function (no others would, oddly enough) this ASUS laptop, and my EeePC Netbook. Everything is a tad slow on the netbook just after the splash screen, but I've never seen it to be slow...

(by the way, this laptop uses intergrated NVIDEA graphics, they are getting better, I'm currently using the 185 driver)

aapgorilla wrote:
Interesting tip but what does it do exactly (ie. what is the default graphics system and how is raster different? ) and how to make it the default for every session?

I don't know much about it, but you can read more here:
http://zrusin.blogspot.com/2009/08/2d-in-kde.html
http://zrusin.blogspot.com/2009/08/more-2d-in-kde.html

There is no, as far as I know, easy way to make all applications use raster by default. bcooksley's tip should help for applications that aren't restored from previous session.

I tried raster and it didnt help me at all. I am going to buy a new graphics card at the end of the year because mine is getting a little old for some of my games. I like NVidia and Ill probabl get another one... Unless there is something that works better with Linux/KDE?

I have a related problem with KDE 4.3.2. I've tried it on both Kubuntu and Debian Squeeze on my computer. At some point (quite often during package installs, but other times too), the CPU usage goes up to 100%. At that point everything is sluggish. RAM (2GB) usage is only about 500M and swap is untouched. It happens on both the x64 and x86 versions of Kubuntu Karmic/Debian Squeeze. On another computer (AMD Athlon II X2 215, 4GB RAM, Nvidia 8400) Kubuntu Karmic (x64 version) runs great (about 20% CPU utilization). I did notice that Xorg and plasma seem to use a lot of the processor.

Problematic PC specs:
AMD Athlon 64 4000+
2GB RAM
Asus A8V-VM SE mainboard
nvidia 8600 GTS

Both Debian Squeeze and Kubutu Karmic give me the max CPU usage problem. I've turned off/on compositing; doesn't seem to make a difference. I'm using the recommended restricted nvidia driver. If I restart KDM from command line, it usually fixes it (for awhile at least). I'm using Debian Lenny (KDE 3.5) right now (rock solid) until I can get KDE 4 to run better on this machine.

Where can I begin troubleshooting?

Upgrade to 4.3.3. There's a bug in 4.3.2 that turns on software rendering now and than. Can't tell you how to work around it, but upgrading helps at least in that aspect.