You'll need to supply the full model number -- 7559, 7567, etc.  On screen in setup (F2 at powerup).

We can't tell from the series you've posted, which encompasses many different models.

hi ejn63 the only thing I found is Inspiron 5770  don't  know if this is the one thanks 

Welcome to the Dell Community  @skyman 

To better assist you, the members and I would need the exact model number of your laptop/desktop???

1. Go into your BIOS.

Power-on the system and start tapping the F2 key to enter System Setup.

2. In Windows:

Hold down the” Windows “key and tap the “R “key.

Then type msinfo32 and hit enter.

Best regards,

U2

PLEASE DO NOT POST ANY SERVICE TAGS!!!

The system uses standard DDR4 soDIMMs, 260 pin.

https://www.crucial.com/compatible-upgrade-for/dell/inspiron-17-(5770)

thanks, EJN63 ordered  standard DDR4 SODIMMs, 260 pins fitted job done thanks again