I have samsung galaxy nexus with CM-11 nightly 07-04-2014.
About twice a month I update my version to the latest nightly build and it was pretty good for a while. Unfortunately last time ( for a couple of weeks ) there were two updates which really slowed down my device. Every app starts now up to 10 seconds. Even when I get a phone call sometimes the phone is not fast enough to display me an answer call button. And the network became slow as hell. CM update download over wifi will take up to several hours, while before it was about 5 minutes. However wifi in local network works a bit faster. gprs inet also works very slow. 100K pdf download takes up to 5 minutes, while it was up to 10 seconds before.
I tried to downgrade to the last stable version I had ( it looks like any before 03-25 ), but without success. Important note: I did not perform the whole wipe during downgrade. I only formatted /system and /cache. I also tried to install other nightly builds with the same result.
There is nothing suspicious in dmesg or logcat. Sometimes in dmesg I can see messages about killing some users apps but it seems normal to me.
How to find the root of such slowdown?
And I'm not sure if the whole wipe will help me, as I'd like to save app data and restore it after wipe.