Part of the problem is due to other
computer activity. There is an inherent
overhead with receiving the RF signal,
digitizing it and submitting it to the
computer/software. If there are any other
programs demanding CPU time then things get
lost in the transfer - resulting in a
scambled or incomplete picture. Your TV has
nothing better to do than receive the RF
signal and display it on screen - something
it is optimized for doing. You might also
have a slower CPU that won't allow for the
faster transfer of picture/videos.