RAM DDR4-2666 or DDR4-2400?

[Morash]

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.

[Paul_Tikkanen · Accepted solution]

Hi:

Since your notebook has the 8250U processor, the 'bridge' term does not apply, according to the manual.

I don't even know what the term means since the other processors mentioned in the 'bridge spec' also run at 2400 Mhz.

I cannot find a definition for bridge as to how it pertains to the subject at hand.

Your processor runs at 2400 Mhz, so the 2600 MHz memory downclocks to 2400 Mhz.

I don't believe that HP ran out of the PC2400 memory.

They probably install it for the entire model series.

What should you do?

If it were me, I would buy a chip with matching specs as the one in there now.

[Morash]

@Paul_Tikkanen

Thank you very much for your reply.

Since my notebook is still under warranty, I checked with my local HP Support as well. They informed me that it wouldn't make any difference, but I decided to follow your advice and go for matching specs. I was able to get an identical RAM chip online, and now I'm happily running a PC with 8GB RAM

[Paul_Tikkanen]

You're very welcome.