Want to add RAM to my notebook Dell Vostro 15-3568

[hostile0101]

In manual (page 72) it is written "Maximum memory 8GB" and "Memory speed 1600 MHz":

http://topics-cdn.dell.com/pdf/vostro-15-3568-laptop_owner's%20manual_en-us.pdf

But other guy (in freenode, channel ##hardware) told me that it can rum even 16 GB x2 = 32 GB overall cause CPU supports it. And also he said that the speed limit is 2133.

I want to add 8GB, so overall i want to have 12 GB RAM.

Also, it is written in manual that speed is 1600 Mhz. RAM that already in has writing: "P4-2400T". So 800 Mhz are wasted or i understood something wrong? What is real limit of RAM frequency in this notebook?

So all that i need to know to choose right compatible RAM for this notebook:

1) Type of DDR (DDR4 in my notebook)

2) Frequency (1600 or 2133 or 2400)

I need to know only these two things, am i right?

Thank you.

P.S. https://i1.wp.com/laptopmedia.com/wp-content/uploads/2017/02/IMG_20170221_144810.jpg - motherboard
https://s18.postimg.org/mqke7uf15/SSL20066.jpg - RAM that already in notebook

Also, I can buy these RAMs from my local store:
SODIMM Patriot Signature Line [PSD48G21332S] 8 GB
SODIMM Crucial [CT8G4SFS8213] 8 GB
SODIMM Kingston ValueRAM [KVR21S15S8/8] 8 GB
SODIMM Crucial Ballistix Sport LT [BLS2C4G4S240FSD] 8 GB
SODIMM Corsair ValueSelect [CMSO8GX4M1A2133C15] 8 GB
SODIMM Crucial [CT8G4SFD8213] 8 GB
SODIMM Patriot Signature [PSD48G213381S] 8 GB
SODIMM Patriot Signature [PSD48G240081S] 8 GB
SODIMM Kingston HyperX Impact [HX424S14IBK2/8] 8 GB

Some are 2133, some are 2400. Are they all compatible to my notebook? Thank you.

 

[Dark Lord of Tech]

Crucial Scanner for guaranteed upgrades.
http://www.crucial.com/usa/en/systemscanner

 

[hostile0101]

Crucial Scanner for guaranteed upgrades.
http://www.crucial.com/usa/en/systemscanner

Hello. Thank you very much for your answer and your link.

Very good tool, but it shows only CT98559** models. We don't have them in our local stores.

We have CT8G4SFS8213. Is it compatible with my Dell Vostro 15-3568? ( for example, specs are the same for CT9855951 and CT8G4SFS8213 )

And if yes, why this website don't show it in their compatibily list? They want to sell newer models or what?

Thank you.