minimal:
reqprocessor: 2.6 GHz Intel Core2 Duo or equivalent.
reqgraphics: 1GB*
reqmemory: 4 GB RAM
reqdiskspace: 35 GB available space
reqsystem: Ubuntu 14.04 (64bit) or SteamOS
reqother: *Requires an Intel Iris Pro graphics card or an NVIDIA 600 series graphics card or better with driver version 352.21 or later.

recommended:
reqprocessor: 3.4 GHz Intel i5 quad core or equivalent.
reqgraphics: 4GB**
reqmemory: 8 GB RAM
reqdiskspace: 35 GB available space
reqsystem: Ubuntu 14.04 (64bit) or SteamOS
reqother: **NVIDIA 760 series card or better with driver version 352.21 or later.