just noticed win 7 is showing a shared memory for my gfx card. googled and found something called virtualized video memory where gpu ram is paged on system ram. but I am confused if this has any benefit as ram is much slower than vram. does it help boost performance or merely allow higher resolution textures at cost of some fps?

Virtual memory is a function of the WDDM 1.0 and up and DX10 and up. Basically: don't worry about it.