You really can put all those two modules of 4GB of L, i.e. 1.35V to your current two slots instead of yours 4GB here, do it with ease. You have 1.6V now, but for example you really shouldn't put older 1.6V memory in newest laptops with DDR3L slots, it will be damaged.
I just followed the online recommendations. My IT knowledge is based on personal experience, learn as I go.
After I upgraded, I had a problem with the HP laptop and I had to return it to HP to get fixed.
They told me that it would be 10-14 days to send and return, so I bought a new DELL while I was waiting for the HP to be repaired. Fourteen days is about 13 too long for me to be without a laptop and dependent on a 4.7 inch iPhone. A lot of people rely on nothing but their smartphone for email and surfing. I am not one of them. I would die if that is all I had to use. I would probably revert to becoming a Luddite.
I used the Dell for 18 months. Up until a week or so ago. I turned it on and nothing happened. The repair guy said that I fried my motherboard when I turned it on. Sometimes, things just happen I guess.
So....... I pulled apart my Dell and tried to save the fan, RAM, HD and battery, just in case I can ever reuse them. I returned to the repair center, so they could transfer the data ($25) from my old HD to this computer. I was surprised when he told me that he would have given me $50 just for the screen. Apparently, there is more value in dead laptops than I thought. Too bad I threw it away.
This HP laptop is low end and basic, but I'll use it until it fails and get a newer, more reliable one with SSD and a 1080P screen. It's good enough for now.