1. Give specs and quality settings you're using
Everything on max, including AA. at 1080p, dual monitor set up, but with the game only running on the primary one.
i5 2500k running at 4.4ghz OC @1.26v(had this as a stable over clock now for 2 years)
msi gaming GTX 980 4GB VRAM GDDR5
running the very latest stable nvidia driver.
2. Say what kind of framerate range you mean when you say choppy
I get about a max of 63fps in europolis, which drops to a minumum of 19 for a second or so. It tends to hover mostly around the 30-40 mark according to fraps.
Turning everything to low (keeping @1080p) only buys me another 7fps or so.
3. Give an exact location where you're experiencing this
The only place so far I have noticed frame drop in in europolis, most noticeably in the parts where you walk under the canopy with the green lighting on the floor. Looking up at the canopy makes the fps fly up to 40+.
I would say the issue is when you have lots of objects close to the camera/viewport. The same objects further away don't seem to cause an issue (or not as much).
Its worth noting that at no point does my gpu get over 60% usage, and the cpu about 50% both in spikes.
But the title screen does seem to max out my gpu to 100% for some reason
4. And most importantly, try restart the game and see if the same thing still persists.
I did that anyway when I had issues getting the AA to stay switched on. Which it is now.