musikmachen.de:

After I used the iPad for some time everything slows down in H9 control. I'll try to make a movie of using it right after powering the iPad on and one an hour or two later and get these to you. 

A movie would be helpful if you can get to that.  I've been trying to reproduce this problem and haven't been able to get it to happen for me.  Could you tell me by the way what version of iOS 7 you're running?  Is it 7.1.1. or something earlier?  You can find out by clicking on the Settings app on your iPad, going to General, and the Software Update.  

I have 7.1.1 installed on my iPad, and since so few people have been seeing this problem, I'm wondering if it might be specific to a particular version of iOS?