The Ion2 functionality includes the stuff the Crystal HD decoder does, plus a whole lot more.

The point for the Crystal HD decoder, is that it can be plugged into a system that lacks modern NVidia hardware (eg. most netbooks), to enable them to handle (up to) 1080i/1080p playback.

I'm thinking of adding one to my Samsung N210 netbook (which has no Nvidia hardware), as an internal PCIe card, someday perhaps.

The Nvidia hardware handles full hardware decode, deinterlacing, IVTC, and presentation to the display (etc..).

The CrystalHD chip handles full hardware decode, but something else still has to shuffle the bits to a display.

Cheers