I just upgraded my KDE to 4.7 and experience two very disapointing drawbacks.

1) For the first time I had no other option than accepting the use of KWallet. Now KWallet ask about my password every so often. And it is extremely irritating. I am not comfortable with not having the choice to set my passwords per application (or per account as in KMail). I really hope that there will be a volontary option to use KWallet soon.

2) After logging into KDE, akonadi (more exactly akonadi_agent_launcher) eats 1.7GB of my 2GB RAM. And the system disk is in constant activity for 10-15 minutes, During this time my system is not responsive and in fact useless.

If I can not find a solution to these problems and lack of alternative, soon, my 8 years of KDE usage is over.

You may want to upgrade to 4.8.2 as there are numerous fixes with regards to Akonadi, PIM, and related bits to the stack.
Also, if you are not using Akonadi, did you disable the showing of events in the Plasma clock applet? This will make Akonadi (assuming nothing else is using it) not to start up at login.

I use the stable tree in Gentoo, where KDE 4.7.4 is currently the latest.

I have also tried to disbale "Display events" in the digial clock settings menu (under Calendar). But that does not help my problem. It does not help either to deactivate Neopmuk altogether in in System settings.

Do you use any KDE PIM applications? If not, Akonadi should not start.

I do use the KDE PIM Apps. An din fact those are almso only the apps I use, e-mailing with several e-mail accoutns to attend and keeping a large list of contatcs

That is why I am so frustrated about KWallet suddenly being mandatory, giviing me all these re-typing of my password all the time. If there is any way of going back to enter passwords, per account, in KMail2 please advice.

If KWallet has become manadtory, my oppinion is that developers should go back to a statre where KWallet is totally volontary to use. On my part I will abondon KDE otherwise. After 8 years of great KDE usage I am on the verge to leave it and go for a lighter desktop environment, where I can choose exactly which apps I want to use or not.

Did you try unchecking "enable the KDE wallet subsystem" in system settings -> account details -> kde wallet.

I have been having the same problem. Finally gave up on KDE all together. The only time I have seen more bloated applications was when I was using MS Windows. It's a shame; KDE used to be a fairly decent system. You guys (KDE programmers) want to generate bloat, start working for Microsoft.