What RAM to upgrade? ASUS ROG SCAR II GL704W

[PeterX7]

Hey all, I am looking forward getting my laptop, however I was informed it will onyl have 1x16gb 2666mhz stick module (unknown other info). I would like to know what is the best way to upgrade the ram to dual channel?

Should I get 1x16gb module with matching mhz and cl timing? (what is the CL number of the factory asus ram btw?)
or
I should get a brand new cl15 32gb 2666mhz stick (2x16)?
or
Get a 3000mhz 32gb cl 18 ram (2x16)? (Can I utilize more mhz than 2666, with focuing on battery life?)

[FULLMETALJACKET7]

Run CPUz or open the back cover to see what brand/model it is. Buy another one of the same.

It will work with 3000mhz modules but at 2666mhz.

[PeterX7]

Run CPUz or open the back cover to see what brand/model it is. Buy another one of the same.

It will work with 3000mhz modules but at 2666mhz.

But how much perfomance would i lose if i stay on cl 19 and not cl15?

The ram according to my research is 1 16gb 2666mhz ddr4 cl 19 ram.

[FULLMETALJACKET7]

But how much perfomance would i lose if i stay on cl 19 and not cl15?

The ram according to my research is 1 16gb 2666mhz ddr4 cl 19 ram.

Negligible difference. Don't worry about it.