Upgrading video card for Skyrim

I am currently thinking about upgrading my graphics card in order to have the best possible gameplay for Skyrim, currently my computers specs are:

8GB DDR3
AMD FX 4100-quad core @ 3.6 GHz
nvidia Geforce GT 440 (1GB ddr3)
Asus M5A 78L-M LX Plus motherboard.
(the hardrive and dvd rom are both just the generic ones that i bought for cheap)

My question is this: I am upgrading the graphics card, and while I'm fairly certain which one is the right choice, I would like to be sure and get others opinions. I am deciding between these 2:

NVIDIA GeForce GTX 550 Ti (http://microcenter.com/product/383665/VCGGTX550TVXPB_NV...)

or

NVIDIA GeForce GTX 650 (http://microcenter.com/product/400524/01G-P4-2650-KR_NV...)

So those are the 2 choices, same price ($119), which one should I get?