HOW TO CORRECT THE SLOW CHANGE OF CHANNELS

You can try a search for        clearmybox                 that will dump the guide data and other things on the Genie, it will take a day or 2 to rebuild and any programs set to record will.

So are you implying that the guide data becomes corrupted, or more than is needed?

Are there any other side effects?

There are other things that are dumped when you run clearmybox it is the other things that may cause slow response times. There is always the possibility the hard drive will fail.