Here are the official system requirements for Blade and Soul from NCSoft. Minimum and recommended are detailed.

Blade and Soul System Requirements

 MinimumRecommended
CPUIntel Dual Core / AMD Athlon 64X2Intel Quad Core / AMD Phenom II X4
RAMXP : 2GB / Vista, Win7 : 3GB4GB or above
Graphic CardnVidia Geforce 8600GT / AMD Radeon HD4600nVidia Geforce 8800GT / AMD Radeon HD4850
Hard Disk22GB22GB or above
OSWindows XP (SP3) 32bitWin7 (64bit)
DirectX9.0c9.0c