Wimdows not recognising ram slower performance

[Jadams92]

I just bought a dell inspiron i7559-763blk. I wanted to upgrade the ram so I bought a Kinston ddr3l 1600mhz. Once I first installed the laptop had trouble starting up. Now it starts up fine but with some performance issues. Also Windows isn't recognising the ram. I've done memory tests and all around system checks through dell support assist but everything pass. What could the problem be?

 

[brispuss]

What is the Kingston memory part number please?

 

[Jadams92]

The issue had been resolved. Thanks for the reply though!