PLEASE NOTE THAT THIS GRAPHICS CARD HAS 2 VARIANTS: DDR3 AND GDDR5. THIS IS THE DDR3 VARIANT.

GeForce GTX 850M 2GB is a fast-middle-class mobile graphics card. It is based on 28nm GM107 Core of the Maxwell architecture.

The Maxwell architecture features many improvements and amongst them is the extremely large L2 Cache which allows NVIDIA to produce Graphics Cards with relatively small memory data transfer rates, without causing too much impact on the overall performance. Furthermore, the Shaders have been redesigned and are both more powerful and energy efficient.
GeForce GTX 850M 2GB DDR3 comes with a full variant of the GM107 Core and thus offers 640 Shader Processing Units, 40 TMUs and 16 ROPs, on a 128-bit of standard DDR3. While the central unit runs at 936MHz and goes up to 1084MHz, in Turbo Mode, the memory clock operates at 1000MHz. It has a rated TDP board of around 45W.
The DDR3 variant is better suited for 720p but it comes higher clocked. Thus it proves to be way faster than GeForce GTX 750M and surpasses slightly the higher positioned GeForce GTX 760M. In fact, it should be pretty close to the desktop GeForce GTX 750.
This card should be paired with a Very Strong Dual Core Processor or a Decent Quad Core and at least 8GB of RAM.