Ram compatibility issue

[adarsh432]

Hi, I am looking to upgrade my laptop ram to 8gb. currently I have a 4gb samsung m471a5244cb0-ctd ram running.

spec:

M471A5244CB0-CTD00
Organization : 512M x 64 Composition : 512M x16 *4ea Used component part # : K4A8G165WC-BCTDM00 # of rows in module : 1Rows # of banks in component : 4Banks 2BG Feature : 30.0mm height & Double sided component Refresh : 8K/64ms Bin Sort : TD(DDR4 2666@CL=19) RCD Vendor and Revision : PCB Rev 0.0

So I need some clarification regarding the ram speed. I can't find ant 2666Mhz ram , I think I'll buy 2400Mhz ram. So

1.Will that make any compatiability issues or speed problem while running at dual channel

2.What will be the  ram speed, if I install 2400Mhz ram with 2666Mhz ram?

3.Does Module Organization 1Rx16 (Current 4gb ram)really matter. Because Do I need to be specific when I buy the new ram with same module organisation.

4.My task manager shows ram speed at 2400Mhz but these are the cpu-z a results which shows 1333Mhz running at 2666 why is that?

I'll attach the pictures below:

cpu-z:

Hw info:

General Module Information
Module Number: 1
Module Size: 4 GBytes
Memory Type: DDR4 SDRAM
Module Type: SO-DIMM
Memory Speed: 1333.3 MHz (DDR4-2666 / PC4-21300)
Module Manufacturer: Samsung
Module Part Number: M471A5244CB0-CTD
Module Revision: 0.0
Module Manufacturing Date: Year: 2018, Week: 30
Module Manufacturing Location: 2
SDRAM Manufacturer: Samsung
DRAM Steppping: 0.0
Error Check/Correction: None

Module Characteristics
Row Address Bits: 16
Column Address Bits: 10
Module Density: 8192 Mb
Number Of Ranks: 1
Device Width: 16 bits
Bus Width: 64 bits
Die Count: 1
Module Nominal Voltage (VDD): 1.2 V
Minimum SDRAM Cycle Time (tCKAVGmin): 0.75000 ns
Maximum SDRAM Cycle Time (tCKAVGmax): 1.60000 ns
CAS# Latencies Supported: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
Minimum CAS# Latency Time (tAAmin): 13.750 ns
Minimum RAS# to CAS# Delay (tRCDmin): 13.750 ns
Minimum Row Precharge Time (tRPmin): 13.750 ns
Minimum Active to Precharge Time (tRASmin): 32.000 ns

Supported Module Timing at 1333.3 MHz: 19-19-19-43
Supported Module Timing at 1200.0 MHz: 17-17-17-39
Supported Module Timing at 1066.1 MHz: 15-15-15-35
Supported Module Timing at 1000.0 MHz: 14-14-14-32
Supported Module Timing at 933.3 MHz: 13-13-13-30
Supported Module Timing at 866.7 MHz: 12-12-12-28
Supported Module Timing at 800.0 MHz: 11-11-11-26
Supported Module Timing at 733.3 MHz: 11-11-11-24
Supported Module Timing at 666.7 MHz: 10-10-10-22

Minimum Active to Active/Refresh Time (tRCmin): 45.750 ns
Minimum Refresh Recovery Time Delay (tRFC1min): 350.000 ns
Minimum Refresh Recovery Time Delay (tRFC2min): 260.000 ns
Minimum Refresh Recovery Time Delay (tRFC4min): 160.000 ns
Minimum Four Activate Window Delay Time (tFAWmin): 30.000 ns
Minimum Active to Active Delay Time - Different Bank Group (tRRD_Smin): 5.300 ns
Minimum Active to Active Delay Time - Same Bank Group (tRRD_Lmin): 6.400 ns
Minimum CAS to CAS Delay Time - Same Bank Group (tCCD_Lmin): 5.000 ns

Features
Module Temperature Sensor (TSOD): Not Supported
Module Nominal Height: 29 - 30 mm
Module Maximum Thickness (Front): 1 - 2 mm
Module Maximum Thickness (Back): 1 - 2 mm
Address Mapping from Edge Connector to DRAM: Standard

[Huffer]

Nothing you posted actually shows it running at 2666 (2 x 1333) it just shows the module you have is theroretically capable of running at that speed on the right motherboard. Your memory is running at 2400 (2 x 1200). I found another module just like the one you have:

https://www.ebay.com/p/Samsung-4gb-Ddr4-Pc4-2666v-Laptop-Memory-RAM-M471a5244cb0-ctd/15019068252?iid...

You can, however, mix a DDR4-2400 SO-DIMM module with the DDR4-2666 module and it will all run at 2400 and as long as you get a module with the same characteristics (single rank) it will almost surely run in dual channel mode for you. The system is not capable of running its RAM any faster than 2400. 

Post back with any more questions and please accept as solution if its the info you needed. 

[adarsh432]

then what is this 2666 means in the samsung ram?

[Huffer · Accepted solution]

I said this:

the module you have is theroretically capable of running at that speed (2666) on the right motherboard

So it is DDR4-2666 memory. If placed on a motherboard that is capable of supporting 2666 speed it would run at 2666. HOWEVER, your laptop's motherboard cannot run the memory faster than 2400. So look at all the shots you posted for actual operating speed ("current memory clock" "DRAM frequency") and it is 1200 or very close to it. I really do not know how much clearer I can try to make this.