how fast is the tv capture?

[ldisplay]

I am using an old pc at the moment just to play around.

now my old pc tends to lag a bit when it comes to things like an xbox/ps2 ect using my capture card(it to is an old version from 3-4 years ago).
if I get a new pc and a good tv capture card will I still have that problem?

as well this is a basic yes/no question hdmi some motherboards I see have it already but as long as it is nividia based will hdmi work?