Question ram problem

[farias fanning]

i have a 2gb ram laptop and its working fine for the use, but i have another 2gb ram that i wanted to install ,
now windows showed me that i have 1.88 gb usable storage and when i have installed the another 2 gb windows showed me that i have 4gb memory and 2.65 gb usable memory.
now could it be that my another ram isnt working properly knowing that window memory diagnostic showed me no errors with my memory ?

 

[Ralston18]

Make and model laptop?

Hardware specs? Windows OS version?

RAM modules: manufacturer, specs?