15.6"
MSI
GP60-2PEY, i5-4200H + Nvidia GT840M + (1920x1080; anti-glare) @RM2899[Dynaudio], 4GB, 750GB HDD, W8.1
GE60-2OC, i5-4200M + Nvidia GT750M(GDDR5) + (1920x1080; anti-glare)@RM3099, 8GB, 750GB(7200rpm), W8, steel series KB

Oh its not just the RAM that's different
The CPU and GPU are different too... The reason why I recommended the 2nd one is because it runs on a better GPU. Since you will mostly be running your games at FullHD (1920x1080) resolution, it makes sense to get a graphic card capable of support your games at such a high resolution (higher resolution = more workload for the graphic card).
The GT750M, although older generation, is still slightly better than the GT840M, and its good to have~

Some might argue that with better driver supports, the GT840M will perform better too and its plausible... so its really up to you la haha, since the GP60 is abit cheaper anyways Its a close call... maybe you can read up reviews on GP/GE series and decide from there (based on ergonomics, cooling etc.)

**Din't recommend 17.3" notebooks since most people are not okay with the weight and size haha, if you are okay with it then can consider too albeit the slightly higher price tags.
** No matter what, don't go for the models with GT740M, those are simply too "weak" for gaming at FullHD

Just my 2 cents ~