Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

[Guest]

For ages now we've been running low powered (256 or 512Mb RAM, Via CPU & chipset)
thin-clients booting LTSP 4.X that initiate an XDMP session onto a fairly chunky multi-way
Opteron Kubuntu Hardy based server. The KDE 3.5 desktop was great
for our purposes and it's all been working fine.

With Lucid LTS having had a while to settle and the impending 'death' of KDE3.5 and Hardy,
I thought I'd get up a spare server and start testing the latest and greatest LTS Kubuntu in
advance of moving our systems over to it.... so that's what I've spent the last couple of days
doing and it's all become something of a nightmare :-(

If I boot my thin clients without glx modules in Xorg (ie with the the vesa driver) then
the desktop performance is truly dire and becomes unusable.

If I boot them with the (Xorg detected) Via drivers and glx then Kde crashes out just after
showing the initial desktop and panel. The .xsession-errors file is some 38K long! but the
point of failure seems to be "kdeinit4: Fatal IO error: client killed".

I've started off with kubuntu-10.04-alternate-i386.iso and upgraded via apt to the
latest versions of everything; I've even added the kubuntu-ppa and installed
KDE 4.4.5 but there's no difference.

FWIW, using a Gnome session on the same server and thin-client works fine as does
Xfce4 (although with glx, compositing turned on and shadows and transparency it's not a snappy as
without but proves the point that Xorg/glx in itself isn't the problem) so I don't think it's the
thin-client(s) or LTSP that's the problem but something in KDE4/plasma/etc.

I even tried putting Kubuntu Lucid on a USB stick and booting that on two variants of my
thin-client hardware but the X session crashes as it fades in the icons on the splash screen
Again, the Ubuntu Lucid works fine in this mode.

So..... am I flogging a dead horse trying to use KDE4 on modest hardware? Has
anyone else got a similar setup working? Any suggestions on where to go from
here?

Perhaps KDE4 is just too heavy on the graphics for any non-local X display... but I
hope someone will tell me otherwise.

[GreyGeek]

Re: Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

Perhaps KDE4 is just too heavy on the graphics for any non-local X display... but I
hope someone will tell me otherwise.

I wish I could, but IMO, controlling a KDE4 desktop remotely takes a powerful machine on both ends of the connection, and the connection better be broadband. I connected this notebook (dual core, 2.67 GHz CPU, 3 GB RAM) with an HP laptop (dual core, 3 GHz, 4GB RAM) on the same network segment ( one was 192.168.1.100 and the other was .101, behind the same Linksys WRT54GL wireless router but using cat5 cables instead). I used krfb/kdrc, xvnc, tightvnc and some others, including nxnode, nxclient and nxserver. KDE4 just requires too much traffic. It will run better on an 8 year old Pentium 4 with 512KB and a slow HD.

IMO, Xfce4 would make a better desktop for remote viewing/control.

[sithlord48]

Re: Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

i have to sadly second what GG said above.. on my server (using NX to do remote X-server) kde is no where near as fast remotely as gnome,xfce or lxde. although i don't agree with his DE suggestion i would say try lxde since it will "feel" more like old kde 3.5 that you used to. (lubuntu-desktop package to install it if u didn't know)

[GreyGeek]

Re: Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

I haven't used lxde so I can't speak from personal experience.

I did google the difference and noticed that lxde uses less RAM than xfce4, as reported by more than one individual.

I don't think a person could go wrong using either.

I tried Xfce4 and found it lacked the punch I wanted in a desktop environment. So now, for my "remote" work I have the owner of the target machine fire up Skype and share his/her full screen. Then I direct their mouse and keyboard movements by voice and chat box. Call it an "intelligent vnc"!

[linuxforall]

Re: Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

In this case, lxde would be my one and only choice, KDE is for desktop/workstation use. Interestingly, in that environment, it feels snappier than Gnome, xfce and others.

[Guest]

Re: Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

Ah... I didn't actually say but our thin-clients are all
on LANs (100mbit).

Is there any downside on people using KDE4 apps like
Kmail (which my users are used to) under a different
desktop?

Is it just the plasma desktop that's the graphics hog?

[sithlord48]

Re: Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

Ah... I didn't actually say but our thin-clients are all
on LANs (100mbit).

Is there any downside on people using KDE4 apps like
Kmail (which my users are used to) under a different
desktop?

Is it just the plasma desktop that's the graphics hog?

basicly its just plasma-desktop thats the hog..

[JontheEchidna]

Re: Kubuntu Lucid/KDE4 hopeless on thin client :-( Any ideas?

Another thing you could try, is using a less gradient-intensive widget theme for KDE, like Plastique or something. The gradients really kill performance over the network, and can tend to not look so great at the same time.