Hello, let me clear up these questions you are having.
First, stick with the laptop we originally linked. The first one byogamingpc linked is out of stock, and because it was more of a test run for the system there is no telling if there will be more. It has a few advantages, but nothing is a huge advantage.
The second laptop which you yourself listed:
http
/www.newegg.com/Product/Product.aspx?Item=N82E16834314183
Is a good bit worse. While it has a better CPU, the graphics in the system are much lower and over all not worth it.
Finally for the laptop byogamingpc suggested last:
http
/www.amazon.com/gp/product/B00DKFFFXO/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B00DKFFFXO&linkCode=as2&tag=b0b929-20
It is a complete trade off and a viable option, but again not completely superior. The CPU is better and by a decent margin. If you are only doing web browsing, videos, typing, and games you will not notice much about the increased CPU performance. While the graphics chip in the system is significantly worse. CPUboss is the worst type of comparison to use.
http
/www.notebookcheck.net/NVIDIA-GeForce-GT-720M.90247.0.html
This gives more information on the graphics processor. The graphics processor in terms of graphics performance is probably about 1/3rd weaker than the other. On top of that the width of the data paths between on the dedicated RAM and the Graphics processor is only half as wide. At best I would say the 720M will give only 75% of the performance of the 8750M, and thats really a high estimate.
Thats also leaving out that the APU inside of the system has a second graphics processor. You have not only the 8750M but you have the 8550G. You can crossfire with these two graphics and use both of them at the same time giving you another large boost in performance in graphics over the other laptop.
So if you wish to have pretty decent graphics and a better processor get the Intel based laptop off Amazon, but if you want a bit worse CPU and significantly better graphics for gaming get the laptop we listed at the top of the page.
ANd as for RAM, I am still debating if I want to buy the laptop off Newegg at the top of the page myself, my only other consideration is to wait until Janruary for the next evolution of AMD processors. However, if I buy the one off Newegg, for an extra $60 you can buy an 8GB stick of RAM and place in it giving the system 12GB of RAM. That would shore up one of the weaker points of the system and make the system quite powerful all around.