Which second bar to choose for a Dell laptop?

Question

Iron

I want to take a RAM to my laptop.
Now installed 1 bar from Samsung for 2 GB.
1333 MHz.
I think to take another 1333 MHz bar for 4 GB, will it be normal?
I heard that the planks must be necessarily equivalent, that is, 2x2 or 4x4, but I get 2x4.
Or if I take the bar for 2 GB, then the speed of work will be SIGNIFICANTLY higher than that of 2x4 GB?
ZY.note 2012, so I won’t give more than 2 rubles for RAM.

Answer 1

See that the timings are the same, for 4GB you can, the company is not necessarily the one that the tkby now has, but it is recommended. On the occasion of speed - 2GB - suffering .. so you will feel the increase, but again everything will rest on the speed of the hard disk later, on laptops they are brake. However, I still advise you to give you another 4GB plate)

Answer 2

I would put two identical bars of 4

Answer 3

In principle, any