I've been using Sonar since 8.5 on dual 22" monitors but I feel it's time to get a bit more screen real-estate.
 
It's simple enough to choose a 37-40" 4k display, but my current graphics card won't go to that resolution, so I need a new one.
 
Would Sonar be able to take advantage of a high end NVidia GForce 10 series or would I be better off getting a cheapish GT7xx series and spending more on the monitor? My DAW is never used for games.
 
Neil
 

I use SPLAT at 4K and I got the least expensive graphics card I could find that supported dual monitors at 4K.  It works flawlessly. I don't think SPLAT will benefit from a more expensive graphics card unless you want to run SPLAT inside of OCULUS RIFT.

I'm using an older GT640 to drive my 43" 4K.  I was using dual 21.5" 1920s.  Twice the pixels with no frames is great!!
 
I chose the 43" based on the desire to have roughly the size elements displayed.  I went from a PPI of 102 to 98, so I could've gone an inch or two smaller - but I do appreciate the display size.
 
Here's a PPI calculator to help you understand up front whether or not you'll be squinting when you make the change
http://kingscalculator.co...xel-density-calculator