To hit the lowest prices many makers omit the second socket but leave the circuitry unchanged. You saw this all the time with PCI and PCIe slots. Just run a Speccy report and you find, almost every time more PCIe slots than what's in a PC.
No mystery here.
Also the Official Max RAM is 4GB. http://www.crucial.com/usa/en/compatible-upgrade-for/ASUS/x551ma
And yes, some may find 8GB works but you can't complain if it doesn't.
-> ALL THAT ASIDE. If you are trying to eek out a little more speed overall, I suggest you replace the standard HDD with a SSD.
So I have a ASUS X551MA notebook with 4 gigs of RAM and windows 8.1 When I look in the task manager under performance, it says I have 3.8 gigs usable of 1333 MHz SO-DIMM, but only 1 of two slots used.
I have completely taken this laptop apart and I only have one slot why does it say i have two.
Is there some sort of soldered memory somewhere or can I upgrade to 8 gigs because i have seen people upgrade theirs with no problem and my CPU can support it, but I'm unsure because some of the X551MAs motherboards have two slots while the others have 1, and there is a lot of different people saying different things.
P.S. My CPU is a Intel celeron N2830 at 2.16 GHz (max 2.4)
P.P.S. Also i have found that when running a game like CS:GO, only 2000 Mb(approximately) are being used with another 1700 unused why is that, a limitation for the application to use, or a limitation for the computer to use. I have that, plus 114 Mb for hardware, and about 50 Mb that is "modified", whatever that means.

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