KDE 4.7: very slow and high disk usage

Question

Since upgrade to KDE 4.7 on my i686 laptop, my system behaves weirdly. I noticed a slow down caused by a very high disk usage: when the HDD spins the cpu usage reported by the CPU monitor plasmoid is very high (~ 50%), while top reports a very small CPU load. Another strange symptom is that, when I try to close the session, the system freezes for about 15 seconds before the logout/shutdown/restart dialog window appears, again with HDD spinning furiously. If I exit the dialog window and then try to close session again it works smoothly, so I think some caching is at work at second try.
This is very painful since it slows down my workflow. Since now I tried to:
- disable nepomuk, strigi and all that using the nepomukcontroller plasmoid
- disable compositing
- delete .kde folder
- uninstall and reinstall all kde packages
without any benefit. On the same laptop I have dual boot with a 64 bit arch installation, which does not have the same problem, nor has it my 64 bit desktop pc.
Does anyone have similar issues? I don't understand what is it that makes the HDD spin so much, nor how to eventually track it down (are there som HDD usage profiling utilities?). Moreover, why top and CPU usage plasmoid report so different CPU usage stats?
I'm very confused, so any help will be greatly appreciated.

Answer 1

Although I'm not having any of the issues as Snack, I have found KDE 4.7.0 to be a very horrible release. In fact, I'm sick and tired of the KDE release notes bragging about killing thousands of bugs each release, when in actuality the first few revisions of each stable release are horrible. When I first upgraded, I ran into at least four really nasty bugs. Although I've worked around some of them, it left a really sour taste in my mouth. Here is what I've experienced:
1.) With a new user or fresh install, there is no wallpaper by default, even if I install kde-wallpapers before I log in, it makes no difference.
2.) Sometimes kwin will crash during log out.
3.) Worse yet, if I exit a full screen game, it will more than likely crash Kwin. This is a problem on my laptop (which has intel video) and not my desktop (which has nvidia video). If I don't remember to disable desktop effects before opening a game, I may run into a problem.
4.) Although my performance is good, it's not great. I would think a laptop with a Core i5 processor and 8GB of RAM would run faster than it is.
I have tested XFCE for a bit, and I do like it alot. However, with XFCE I am unable to browse Samba shares, and that is a huge problem. In addition, I find KDE's applications to be much better than what ships with XFCE, but I question whether they're worth the performance hit. I really love Kate, Gwenview, Digikam, and Amarok. I know you can install those in XFCE, but they feel out of place and then my desktop pretty much becomes a mutt. Not only that, but KDE is full featured, whereas XFCE is not. It's like I have to choose between a stable desktop or a desktop with full of bugs.
I hope that KDE 4.7.1 fixes everything, but historically it's usually the 4.x.2 release that really does the trick.