Serious RAM upgrade confusion

[Adonix]

Hello community,

Recently I purchased HP Pavilion 15-cc134tx laptop.

Upon checking official HP website for laptop description, it says installed RAM 8GB 2400Mhz. (https://support.hp.com/au-en/document/c05881900)
Upon checking from CMD utility in windows "wmic memorychip get speed", it says 2400Mhz rate.
Upon checking memory details from task manager, it's showing 2400Mhz speed.
BUT upon physically opening laptop back panel and looking at the installed RAM inside is 8 GB DDR4-2666 SDRAM kingston.

Can someone please guide me which is the right RAM for this model?

Should I purchase 8GB 2666Mhz speed RAM or 8GB 2400Mhz RAM 1.2V?
I want to upgrade the RAM from 8GB to 16GB.

Help appreciated.

[Paul_Tikkanen]

Hi:

It is usually recommended to purchase a matching memory module of the same specs.

But if it is cheaper for you to install 2400 MHz memory in there, that would be OK too.

The 2666 MHz memory module will downclock to 2400 MHz.

The service manual is of no help because it indicates that 2400 MHz memory modules are used which downclock to 2133, and that would only be the case for some of the 7th gen core, or pentium processors.

http://h10032.www1.hp.com/ctg/Manual/c05705784

The crucial memory site indicates you can install 2 x 16 GB of memory, and they are usually right.

https://www.crucial.com/usa/en/compatible-upgrade-for/HP-Compaq/pavilion-15-cc134tx

[Adonix]

So if I install 2400Mhz memory with my existing 2666Mhz memory, will my system will reflect 2133Mhz memory speed in task manager/cmd?

[Paul_Tikkanen · Accepted solution]

No.

The 2400 MHz memory will run at the full 2400 MHz speed.