FYI. I purchased a Dell Inspiron 15 7548 laptop. I've had it 10 days. I got an email 3 days ago from Dell saying there was a "system error" and my computer does not have the AMD Radeon R7 M270 4GB DDR3 graphics cards, as advertised. Instead Dell says it has an Intel HD Graphics 5500 graphics card. I have a option to get $50 back for their error or send back the computer within 7 days. I'm not a gamer and don't plan to watch many movies on the laptop, so I'm not too upset. Others might be, so I wanted to share. I also cannot determine the difference between the two types of graphics cards.
The question about graphics cards remains unsolved. Nevertheless, your DELL may NOT have this card, as promised.