GeForce GT 740 v2 Gainward 2GB Edition is a special edition of the middle-class GeForce GT 740 v2.
This edition comes with a custom cooling solution which will not yield any performance boost, as GeForce GT 740 v2 does not benefit from the GPU Boost 2.0 technology.
Furthermore, the frame buffer was doubled to 2GB though this will not boost its performance and can be addressed as a gimmick - marketing to lure consumers into paying more for the same product.
Since it doesn't come overclocked out of the box, its performance is exactly like the reference GeForce GT 740 and thus GeForce GTX 650 is still faster.