What are you doing that is causing the "glitch and interruption" ?

nothing actually, even when computer open, the voice normally come out from speaker but the voice glitch, I can hear it. and in videos also there is still malfunction. 

Additionally, movement of mouse is not properly in some time too. 

Could it be related with speed of RAM? or

@elvin14 

Ok then.

To start with you had only 4gb of ram.

That in itself could cause the "Glitching" you describe.

Adding the 2x8gb was a good move.

And the 3200Mhz SHOULD be no problem as long as you do not have the Nvidea MX330 installed.

NOTE Only systems configured with a discrete graphics card will support 3200 Mhz memory.

https://www.dell.com/support/manuals/en-us/vostro-14-3400-laptop/vostro_3400_setup_specs/memory?guid=guid-d56522c0-055f-4af4-acd6-be06b36d77ec&lang=en-us

You could try going to:

System Properties, Advanced, Performance Options Visual Effects, CLICK "Adjust for Best Performance" and Apply.

Then try increasing your "Virtual" memory.

Best regards and good luck,

U2

Welcome to the Dell Community  @elvin14 

Do you have the Nvidia discrete graphics???

Best regards,

U2

No, it is not NViDIA, it is intel graphics.

Thank you so much,

Additionally, what could be my problem, when I try to open it with 2 8gb RAM (this happened before also) it does not open and sometimes I have to wait for a long time sometimes more than 4 minutes. 

At the same time I just wait for it may be solve but there is still malfunction the voice in the video or music. And Laptop opened in more than 1 minute. 

Thank you so much,