Notebook Hardware and Upgrade Questions

Hi all,

My new laptop came with 4GB RAM, and I need to add another 4GB. I checked the memory module specs in my laptop’s Maintenance and Service Guide and this is an excerpt:

“DDR4-2666 bridge to DDR4-2400 dual channel support (i7-8565U, i5-8265U processors)

DDR4-2400 dual channel support (i7-8500U, i5-8250U, i3-8130U processors)”

So in a perfect world, since my CPU is i5-8250U I should get a 4GB DDR4-2400 module, and end of story. I thought it would be better to match with the existing module so I looked it up using HWiNFO and CPU-Z, but was surprised to find it DDR4-2666 not 2400 as supposed to be, although actually running at 2400MHz as shown in the screen shot!

 So now I’ve become confused and have 3 questions:

1. Does this mean that my laptop has a DDR4-2666 bridge to DDR4-2400 instead of just DDR4-2400 as shown in the manual? Or maybe HP just simply ran out of DDR4-2400, so they used a higher compatible module?

2. What is this DDR4-2666 bridge to DDR4-2400 anyway, and what’s the use of it if it will be running at the lower speed of 2400MHz? Moreover, I looked up i7-8565U and i5-8265U CPUs on Intel website and it specifies DDR4-2400 for both not 2666! So why is HP using this bridge for them?

3. Which speed should I get for my laptop, 2666 or 2400? Even though it’s a bit more expensive and it doesn’t really make much sense to me since it will be running at 2400 only, I feel more inclined to getting 2666 in order to match with existing. Should I do this, or follow the manual?

Appreciate your replies.