Check Memory configuration in Windows

Click Start

type "Command Prompt"

Right Click, Run as Administrator

C:\WINDOWS\system32>wmic memorychip get manufacturer, devicelocator, partnumber, capacity, speed
Capacity    DeviceLocator  Manufacturer  PartNumber        Speed
8589934592  CPU0-DIMM1     Hynix         HMA41GR7MFR4N-TF  2133
8589934592  CPU0-DIMM8     Hynix         HMA41GR7MFR4N-TF  2133

Which means:

8GB DIMM-2133Mhz Module - Hynix HMA41GR7MFR4N-TF

Features
Weight     0.1 lbs
Dimensions     5.125 x 0.039 x 1.181 in
Rank    1Rx4
Cas Latency      CL15
Height     STD
Made By     SK HYNIX
Voltage     1.2V
Speed     PC4-17000P-R
Error Correction Code     ECC
Kit Qty     1x 8GB
Technology     DDR4-2133
Form Factor    RDIMM

This HMA41GR7MFR4N-TF, SK Hynix 8GB (1x 8GB) Single Rank x4 PC4-17000P-R (DDR4-2133) Registered CAS-15 Memory Kit made by SK HYNIX