I'm thinking to buy new RAM (for Lenovo 320 15AST, motherboard is LNVNB161216). I had 4GB, I need 8GB. My current RAM is m471a5143sb1 2133Mhz, CAS (CL) 17, PC19200.

I was looking at two with such specs:

Crucial [CT8G4SFD8213] 2133 Mhz, PC17000, 15-15-15-36

VS

Patriot Signature [PSD48G240081S] 2400 Mhz, PC19200, 17.

First is a bit cheaper, has frequency that no more that baseboard provides, lower latency, but lower PC (also I'm not sure which PC my baseboard provides).

Command su -c 'dmidecode -t 17' shows that Speed is 2133 MT/s But specs on internet for my RAM (m471a5143sb1) tell that it has 2400Mhz. Does it mean that my motherboard locks down RAM's frequency ?

lscpu gave me this:

CPU family:          21
Model:               112
Model name:          AMD A6-9220 RADEON R4, 5 COMPUTE CORES 2C+3G
Stepping:            0
CPU MHz:             1491.819
CPU max MHz:         2500.0000
CPU min MHz:         1300.0000

I was looking if there settings that locks down RAM, it seems there no, but I not sure, so I'll put these photos here:

I'm thinking to buy new RAM (for Lenovo 320 15AST, motherboard is LNVNB161216). I had 4GB, I need 8GB. My current RAM is m471a5143sb1 2133Mhz, CAS (CL) 17, PC19200.

I was looking at two with such specs:

Crucial [CT8G4SFD8213] 2133 Mhz, PC17000, 15-15-15-36

VS

Patriot Signature [PSD48G240081S] 2400 Mhz, PC19200, 17.

First is a bit cheaper, has frequency that no more that baseboard provides, lower latency, but lower PC (also I'm not sure which PC my baseboard provides).

(I think I'm gonna go with this one: SODIMM Crucial [CT8G4SFS824A] 8 GB)

(I have this question on superuser, I just had to move it here, there also answer already, but if you have something to add you're welcome)