How to know what RAM to buy for a laptop?

Question

laptops

Good afternoon.
A relative asked me to buy him additional RAM for a laptop ( ASUS K50IJ: market.yandex.ru/model-spec.xml?modelid=4789815&hi... ), but when we unscrewed the cover to see what was there and how, a surprise awaited me:
Photo: habrastorage.org/files/7fd/532/3dc/7fd5323dc57f457...
I did not take anything out, what is shown by default is shown. I understand that these 8 chips of 128 MB each have that built-in memory of 1 GB. But where and how can I find the right bar to build up my memory?
I'm going to Moscow in a month, but first I need to make a choice. Tell me please.

Answer 1

By your own link

DDR2 800 MHz

Look in the manual for the laptop how much memory it supports and choose.
Accordingly, you need a bar no more than 2G, SODIMM, DDR2 667 or 800 MHz