Quadro K4000M is a high-end business card based on the 28nm, Kepler architecture.
Technically the successor to the previous Quadro 4000M, it's based on the Kepler GK104 (despite the SPU count) and offers 960 Shader Processing Units, 80 TMUs and 32 ROPs, on a 256-bit memory interface of fast GDDR5. The central unit runs at 600MHz and the memory clock operates at up to 700MHz.
Quadro K4000M's drivers are certified for professional applications. Therefore, and also because it's underclocked, its performance lies closer to GeForce GTX 675M despite the similarities to GeForce GTX 675MX.