Hello,
I installed Kubuntu 10.10 with KDE 4.5 and the open source Nouveau graphics driver on my Lenovo Thinkpad T61 with NVIDIA Quadro NVS 140M graphcis card. The screen froze many times and I so had to restart the whole system each time. I finally decided to install KDE 4.6.1 (from ubuntu mavericks backports) but the problem remained. I then replaced the open source Nouveau graphics driver with the proprietary NVIDIA driver (nivida-current) 260.19.06. The good news is that the screen does not freeze anymore but the bad news is that all KDE programs react very slowly. Any ideas how to fix this?

Thanks,
Oliver

disable desktop effects, does that help? if so re-enable effects but disable blur

on desktop effects module -> advanced tab -> what is composting type? try switching to other one
same for enable direct rendering

You should also consider that the slowness might not be graphics related
1) cpu - open ksysguard and look at the cpu column any process eating all your cpu?
2) ram - in Konsole type "free" what is the swap line look like, if the used column is high than your using swap (disk) and this would slow things (paste results here)
3) io - in Konsole run "iotop" (may need to download) is any thing thrashing your harddrive?
4) strigi/nepomuk try disabling

Hello,
thanks for your help. desktop effects are disabled anyway. By the way, I have a 2 GHz dual core CPU and 2 GiB of RAM

1) Kysysguard: in the tab "System load" the CPU load goes up to 100% for example when I change the size of the window running Dolphin file manager or open another KDE program.
In the tab "Process table" chromium, Dolphin, plasma, ksasguard consume between 0% and 4% CPU each
2) 0.97 GiB of 1.97 GiB used
3) iotop: no problems detected
4) I disabled Nepomuk Semantic Desktop and Strigi Desktop file indexer. This seems to really help quite a bit.

If Nepomuk and Strigi are the problem then I wonder why this causes so much load on a system with 2 GHz dual core and 2 GiB of RAM???!!!!

How old is your KDE install? Normally indexing is done in the background and the initial process can be disruptive to normal work but you shouldn't really notice it after that - I certainly don't on my T61 (2.2 GHz dual core and 2GB RAM).

I installed kubuntu 10.10 about 4 weeks ago.

toad wrote:How old is your KDE install? Normally indexing is done in the background and the initial process can be disruptive to normal work but you shouldn't really notice it after that - I certainly don't on my T61 (2.2 GHz dual core and 2GB RAM).

Thanks.

Is this something that always crops up? Next time it happens please open a terminal and type "top" - if you see processes which use near 100% CPU (like kde4d or kde4notify) you can safely kill them.

I would suggest you remove the strigi/nepomuk folder(s) and config files and then restart it and see if you had something corrupted

Has anyone solved that problem. I've got the same. ;/

Finally I've got solution !!! If You've got nvidia quadro NVS 140m and You want KDE run smooth and nice You have to change your method QT graphic system to RASTER. You can create some script ( for example qtraster.sh) in ~/.kde/env/ with content :

export QT_GRAPHICSSYSTEM=raster

Later, restart kdm and enjoy it!

Works great for me!! ;]

1. If you are running with Direct Rendering, switch to Indirect Rendering. You may get better response times, specially if your Quadro NVS has little VRAM (<= 128MB)
2. You MUST upgrade to Natty. You are running KDE, so you won't suffer the Unity problems, and you'll get some interesting goodies. If you run Natty LiveCD, you'll find that you can enable 3D right in the LiveCD: that's because Nouveau is working great in G8x cores (Quadro NVS 140M is based on NVIDIA 8500M GT, I have a desktop 8500 GT, so your mileage should be like mine). Remember to install Muon.
3. Test if you can maximize your Konsole. If you can't, then a switch to Nouveau, kernel 2.6.39 and xorg-edgers is mandatory.
4. Raster is not a real solution, because it will turn your system into a memory-eater. Try to tackle your problems with HW acceleration, and use raster as a last resort.
5. Disabling Strigi/Nepomuk has NOTHING to do with this, and is in general bad advice. Install KDE PIM 4.6 RC. That will update some Akonadi-Nepomuk indexers that got stuck into KDE 4.4 era, and may improve dramatically your Strigi/Nepomuk performance. The only way for Strigi, Nepomuk and Akonadi to get lighter is to use them, torture them, and report bugs against them.

I am also experiencing the same problem. It might be related to https://bugs.kde.org/show_bug.cgi?id=234463. have a look at the bug report, there are some tips to improve performance there (e.g. https://bugs.kde.org/show_bug.cgi?id=234463#c81)