Showbiz DVD2 vs 2.2.15.106 vhs capture problem

[zulubase]

I'm finding the excellent resolution seen on the preview screen of Showbiz dvd2(VC100U Hardware) as the vhs is captured, seems to become inferior after burning & playing on TV. The vhs tapes vary in length between 1 - 2.5hrs if longer I edit into 2discs to avoid compression & maintain resolution, depending on the length I adjust the Bitrate between 3 & 5, if only an hour long, can get away will 7. TV screens in my area have a height that is 75% of the width, so I use the frame size 720x576, is this correct or might 320x240 create better resolution on the TV.
I'm thinking to upgrade to dual core, 2.6GHz - is a Graphics Card with Video Capturing Capabilities a good thing to add in addition to the VC100U, or instead of? Thanx