Graphic card for Viewport - ATI or NVIDIA


I have a question. I need to buy a new graphics card for my animation project (Blender Internal render).
Currently I have a GF 9500GT 1GB - in Viewport I have 10fps - enough for me.
I tested the project also GTX 560Ti 1GB - 16fps - still not enough.

So I wonder between the GTX 650Ti Boost 2GB vs Radeon HD7850 2GB.

Does in Blender 2.69 AMD/ATI still wins with Nvidia when it comes to viewpport performance?

Which card is better to viewport fps?

My PC:
i7 920 - 2.67GHz
Nvidia 9500GT
Windows Vista 64