I think what is holding you back is not the video memory but the GPU. 7950GT is now more like a midranged video card, and it don't perform very well in many newer games specially in shader-intensive games like UT3 because of the poor shader power that 7 series have
I have 8800GTS 320MB, I play at 1680x1050 and I don't think that 320MB is holding me back
I have 8800GTS 320MB, I play at 1680x1050 and I don't think that 320MB is holding me back