Hi,
the Novosun you linked to is a genuine motion controller and would be much better than a parallel port, but I would not choose that one. Novosun peddle pirate copies of Mach3
and get NO support on the Mach forum.
If you want to buy a motion controller buy a US or European made one, don't buy Chinese rubbish.
UC300
57CNC
Ethernet SmoothStepper
Hicon
are all good.
The second board you linked to is just a parallel port breakout board, it won't help your PC which is suffering from excess jitter.
Craig