memory dual channel

[Regiusfake]

Dear all, 

I recently bought and installed a further 8Gb ram bank on my HP Laptop 15-bs0xx. If I checked the specifics correctly I should have bought the right one (DDR4, 2133MHz, SODIMM, 260pin). 

After plugging in the component, I noted that the task manager, even after various restarts, was not yet able to detect the new component. Therefore, I checked on CPU-Z software and found the following situation: 

- The SPD panel shows that both the ram slots are occupied and I can see the specifics of each of it.

- The memory panel recognizes that the total memory amounts to 16 Gb (so 8Gb times 2 components). Nevertheless, the same panel also reports that the memory channel is single and not double as it would be needed to make use of both the components. 

After looking for more information on this community, I checked also the mantainance and service manual of my laptop model and it actually says the pc should be able to support dual channel ram. 

Here I paste the link http://h10032.www1.hp.com/ctg/Manual/c05493257

Subsequently, I started to look information to discover whether is it possible to switch manually the memory to dual channel mode and it seems like that something could be done on the BIOS... but I really did not find any trusted or exhaustive guide which describes the procedure. 

Can anybody help me with this issue? I am not a computer scientist or whatever, so I may have done some errors throughout all these procedures. Any help is really appreciated. 

cheers, 

Matteo 

[Huffer]

Please tell us the specifics of the memory you bought and the original memory in the laptop. In order to have dual channel the 2 modules do not need to be 100% identical (same maker, etc) but the same specifications. Original memory is likely DDR4-2400 not DDR4-2133. Dual channel operation just happens if everything is right....no need to adjust anything in the BIOS. 

[Regiusfake]

So, I checked more carefully and this is what I found.

On the task manager, the memory speed is said to be 2133 Mhz, whereas the max bandwidth, which I checked on CPU-Z, is DDR4-2400 (1200 Mhz). 

The extra memory I bought is DDR4, 2133Mhz speed, CL 15, PC4-1700 SODIMM 260pin non-ECC 1.2v

By checking on CPU-Z, its maximum bandwidth is DDR4-2132 (1066Mhz)

https://www.amazon.it/gp/product/B07GPBK5YK/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

So maybe the problem is not the speed but the maximum bandwidth? 

[Huffer]

Speed and maximum bandwidth are related things. I suspect the problem is compatibility. That is a "generic" memory module. If you want dual channel operation I would get a good OEM DDR4-2400 module something like Hynix, Samsung or even Crucial. As I suspected, the memory in your laptop from the factory is DDR4-2400. It is capable of running as fast as -2400 speed but for the motherboard of your laptop which can't run it faster than -2133. So both modules are running at -2133 but subtle differences between the original and new module keep them from syncing and running dual channel.