Having the same problem with stuff popping in pretty close no matter what settings or view distance I choose.
Intel i5 4670K
GeForce GTX 770
Gigabyte GA-Z87X-D3H
Kingston HyperX DDR3 1600MHz
Game installed to Samsung 840 SSD
Win 7 Ultimate SP1 x64
Edit: Just finished a fresh install of my PC. While overall performance improved (fresh install was overdue), the pop-ins persist.
So I can rule out conflicts with previous B&S clients I had installed. Also I'm not having problems with other games.
I tried almost every possible combination of nVidia- and ingame-settings. I noticed the pop-ins are worse in some zones than in others.
It's most noticeable on small foliage like grass. Looks like half of it gets rendered farther away (~20m) and the other half pops in as I get closer (~10m). Bigger textures like rocks, trees and bushes pop in a little sooner, but I can't see stuff nearly as far as some people say they do. Rocks sometimes slightly change shape shortly after becoming visible.
I'm starting to think it's just bad optimization on some systems.