I am down to a choice between GTX 860m 4GB - with i5 (lenovo Y70-70) or GTX 860m 2GB with i7 (Asus G751) - both systems have 8GB RAM and 1960 x 1080 screens. Which would be better for games such as Witcher 3, Project Cars, F1 2015? What is more important more Vram (2GB vs 4GB) or better processor (quad vs duo)? Thank you.