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