I am building a workstation pc, which will be used by a student, studying architecture, using autocad, etc.
Currently I am struggling between choosing 980 or K2200, can anyone give some advice?
I believe newer AutoCAD releases can use gaming cards via DirectX, so I'd say 980.
Cue someone correcting me.
K2200 is a piece of junk, the price to performance even for CAD will be better with a 980. If you don't go higher end withe Quadros it's just a waste of money.
You are correct that AutoCAD can use gaming cards, however the GTX 900 series is not on the certified hardware list for AutoCAD 2015 or 2016, as where the K2200 is. Doesn't mean it won't work, but there won't be much official support if there are issues.
Go with the GTX 980, low end Quadro cards are just to expensive for things they do not deliver.
Edit: I know this from tests we did at my workplace.
Lower end Quadro cards are not good value because the money comes from the support, drivers etc you will be getting with the card.