Hello, I've currently ran into the situation where the shadows on SA Lag when enabled, these are my specs;
Processor - AMD FX 6300 3.7 GHZ 6 Core Processor
GPU - XFX AMD Raedon 6670 (2 GB)
Mobo - 78LMT-USB3
8GB of DDR3 Ram (1333 MHZ)
1TB Sata HDD
Windows 7 Home Premium (x64)