What is the best speed RAM for my Laptop?

[cool666]

I have a Dell Inspiron 15 7559 and I would like to upgrade the RAM as it only has 8 gigs (probs some low quality stuff) and looking to upgrade it to something much faster and bigger and wanted to know what the highest MHz I could put into it is? And also if I could remove the RAM that's already in it for a different RAM module without drawbacks? If it's relevant I play games, watch movies, and edit videos on the go and that's why would like it to be bigger and faster. Any help would be massively appreciated I am a giant noob at laptop modding and not all that confident. I am aware that especially for this laptop adding RAM IS ESPECIALLY easy as it only has 1 or 2 screws on the backplate

 

[algorithmbreaker]

Dell Inspiron 15 7559 system supports (2x8GB) DDR3L 1600MHz memory only.

If you have a single 8GB stick, then just add another 8GB is all. Some quality / performance difference will be with good brand memory such as Crucial, Samsung, Corsair, Kingston,

http://www.memorystock.com/memory/DellInspiron157559.html