Digital/analogue- either way changing the card or even just driver versions - you should recalibrate. I do so every time I make such a change and there are always subtle changes to be made - sometimes just 1-2 RGB ticks, but it's there. Going to a different card especially - there are always changes. GPU make/type, manufacturer design differences, etc. - all change the output slightly, even batch to batch. Yes the data can be delivered digitally, but it's not processed all the same before it gets to the monitor.