First of all, I would like to thank everyone for trying to help.
I have to use this terrain. I tried many programs, including AutoDesk Infraworks, Civil3D, 3DS Max, SketchUp with Instant Architecture and ESRI City Engine. We need to prepare terrain for houses, draw roads and fences. Then we open this model in Lumion and render 3D video animation. So far we got best results with 3DS Max (successfully completed 6 projects), but Chief Architect is the most intuitive program we found so far. Our new architect is using it and he told me that CA can draw roads. I tired it, and definitely CA workflow drastically decreases modeling time.
This is my PC config:
Windows 8.1 Enterprise 64-bit
Intel Core i7 4790K @ 4.00GHz
Haswell 22nm Technology
16,0GB Dual-Channel DDR3 @ 775MHz (11-11-11-28)
ASUSTeK COMPUTER INC. Z97-A (SOCKET 1150)
Display 1: 23'' 2357M (1920x1080@60Hz)
Display 2: 23'' ASUS VS247 (1920x1080@60Hz)
GPU: 2047MB NVIDIA GeForce GTX 760 (ASUStek Computer Inc)
232GB Samsung SSD 840 EVO 250GB (SSD)
931GB Western Digital WDC WD10EZEX-00BN5A0 (SATA)
TSSTcorp CDDVDW SH-224DB
NVIDIA High Definition Audio
I tried, but it didn't help.