GTX 660ti 3GB card issue

[stupiddimbulb]

I have a Gateway DX4860-UB32P, and recently replaced my HD 7770 with this

http://www.amazon.com/gp/product/B008S15X64/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1

I also replaced the PSU with this

http://www.amazon.com/gp/product/B005E98I0G/ref=oh_details_o01_s00_i01?ie=UTF8&psc=1

Oh boy, now all these problems. I updated to the latest drivers, but now Windows 7 takes longer to load, videos I play with VLC stutter, my Windows Experience went from a 5.5 to a 4.7, and all my games run more slowly. Did I screw up and get an incompatible video card? Any help would be much appreciated.

 

[xl2aNd0m]

I've read around that it can be tricky to uninstall AMDs drivers and install the Nvidia ones. Read around the forums people have problems like this all the time (I haven't changed manufacturers yet so I can't say from experience)