One GTX560ti handles everything well at 1080p so 2 should. 10GB ram is strange configuration what sticks do you have there?
There is no work around on the Vram to answer the question.
3x 2gb Alienware/Dell and 1 4gb Pny. It happened by act of trouble shooting, thinking maybe my ram was the problem. And yeah they pack a punch in most games but you get vram hungry games like BF3 or I think Witcher... and things start to crash as soon as I see 1000+ in the corner of my screen.