I currently have a MacBook Pro 15'', QuadCore i7, AMD Radeon HD 6750M, and 4 GB of RAM. I use this laptop for gaming, and just wondering if upgrading from 4 GB to 8 GB of RAM will make a big difference in gaming? I am using Windows 7 through Bootcamp and am able to run the majority of games on max settings such as Dead Island, Left 4 Dead 2 without any lag. However when I run other games such as Shogun 2: Total War, Metro 2033, I seem to lag a lot even when on medium settings. In short, is 8GB RAM the maximum upgrade you can do with a MBP 15'' and will it reduce lag with gaming?