I've noticed that for me, the reason for my slow loading time was due to GeForce Experience. In theory, GeForce should startup when my computer starts and run silently in the background. What was odd was that sometimes it seemed like it was running (e.g. I could see the GeForce FPS monitor on top of my DN screen) but other functions weren't working (like Shadowplay). Whenever this happened, the load times for DN were all over the place. Also, I'd notice that after the matches the textures on my character would take several seconds to appear. If I manually launched GeForce (ideally not while in the game) then those issues would go away. It seems like the GeForce was hanging up the load times for DN. Not sure about GTX without Geforce or AMD (with AMD catalyst).