I've been using Kubuntu for something close to 9 months now and I am 100% happy about it. There's just a problem with my k3b.
Since I reinstalled the system a few weeks ago I can't burn a single DVD without troubles. The burning is terribly slow (1 to 3 hours per DVD) and the device buffer goes all over the place (which I am assuming that it causes the slow DVD burning)...
Is there anything I can do to solve this? I tried burning within a Windows 7 VM with succes but I just want it to work in Kubuntu!

When burning can you confirm that your computer's hard disks are largely inactive?

I don't know how exactly to do that.. but I figure if it works using virtualbox using the same harddrive through a shared folder without any slow burns it's not a hard drive problem...

Any other ways I should/could test to confirm this or is this enough proof?

Can you check in the K3b settings which burning program it is using?

I think its cdrdao but to be sure, here's an image of my settings.

The presence of growisofs indicates that it should work fine.
Could you check the output of "lsof /dev/sr0" (run it a few times and compare the output).

I tried both of these about 5 times in Konsole...

lsof /dev/sr0: no output
sudo lsof /dev/sr0: no output

Nothing happened?

Thx for helping me out so far anyway!

Okay, that is excellent. Unfortunately I haven't got any other ideas - as the problem does not seem to be hardware related, and the drive is not being accessed by other applications in a interfering manner.

Can you do a test burn with another disc burning application under Linux to see if that also experiences the same performance issues?

I'll try using Brasero and come back to you!

I just burned an image using brasero in 15 minutes. Just to be sure it's not just a Video_TS problem (which I tried burning earlier) I am now burning the same ISO in k3b.
Unfortunately the device buffer keeps going all over the place and k3b expects my burn to take 2,5 hours...

So there's definitely something wrong with my k3b.. anything I could try to fix it?

Try removing ~/.kde4/share/config/k3brc to begin with (make sure K3b is closed first however - if ~/.kde4/ does not exist, substitute ~/.kde/ instead)

I just tried the following:
sudo apt-get remove k3b --purge
sudo apt-get install k3b
Burn the same iso using k3b and now my device buffer stays at 99% and the expected burn time is around 15 min...
So there probably was a configuration error somewhere...

Thanks a lot for helping me out! Im really happy I can burn my dvd's in a normal way again!