The switching issue, for me,

The switching issue, for me, cause the brightness of the image to flash.  Mikinho explained that it’s an incompatability between the MS MPEG decoder and the MPEG encoder the network or cable company is using.  I only observed it on certain networks or certain shows and it could be quite anoying.

You can acctually see it by pressing “411” then “info” on a media center remote.  This brings up details pages for the stream you’re viewing (live or recorded).  If you keep pressing your right navigation button untill you get to the last page of the details, at the bottom will be the frame rate.  If it is bouncing between 59 and 29, that is the switching we are talking about.  I can see it switching even now with my new systems but it doesn’t manifest itself as the brightness flashing I had with the 4550 cards.  I do sometimes notice some minor hiccups with the A4-3400 but nothing is nearly as bad as it was.