Hey there. I recently upgraded the TV that was in my room from an 10? year old CRT TV, to a 5ish year old flat screen (it's probably an LCD I think). The problem that I've run is that it doesn't use the whole screen when I boot unleashX and when running games from the HDD. If I boot it to the MS dash it uses the whole screen fine.
The size was already at the max. I found that if I turn the TV off then back on again it's using the full screen. So it's all good.