i also expereinced serious sluggishness in the UI (e.g. transitions among desktop <=> multi running apps<=>mean of icons) recently.

You know, it's weeks after I installed PR1.2. I initially suspected that it's related to PR1.2.

Then I realized that it may be due to the fact that I have been accumulating a lot of mp4 videos shot on the device. I deleted them all from the device and the UI transitions become very smooth like brand new.

Why did I guess it's due to the mp4? It's because I used to be able to play N900's videos on TV by connecting with a cable. Last week I failed to do that. Then I had such a guess.

Now, to experts, may I know why deleting all these mp4 solved sluggish UI problem? Thanks.