Significance of memory with graphics cards

Hi All, Thought I'd come to more IT-savvy people for opinions on what laptop to choose. I am currently between two options: Lenovo Ideapad Intel Core i7-3610qm 8gb DDR3 Nvidia Geforce GT 660M DDR5 2 GB or Asus N56 Intel Core i7-3630qm 8gb DDR3 Nvidia Geforce GT 650M DDR5 4GB Among other things I am looking to use the laptop into gaming thus interested in the performance. Asus has slightly better processor but how then again the graphics card is better on Lenovo. Or does the 4gb on 650M make the difference? Thanks in advance on any help.