Ram Speed Limit

[resistencia]

@emreakaydin 

The problem I see is that you will probably only be able to use one memory module in an 8GB or 16GB slot of a single rank (1Rx8 or 1Rx16). As far as I know, there are no 32GB memory modules of a single rank.

And as the manual indicates, you can only have a maximum speed of 4000 MT/s using 16GB memory modules, reaching a maximum of 64GB. Using 32GB memory modules can reach 128GB but with a frequency of 3200 MT/s.

This is what I think is happening.

[TzortzisG]

@resistencia 

The author wishes to have 5600 speed on this system. Therefore, this particular purchase was a bad decision. The same CPU on other models may even support 6400 (as we've seen on the Omen MAXes). CPU supports 5600 and for reasons unknown HP even uses 5600 RAM modules, BUT motherboard supports maximum speed of 4400.  I think that any other advice we offer is not relevant to the original question. Can this system run DDR5 at 5600? NO.

[resistencia]

I understand that using only one slot may give you 5600 MT/s, but the memory must be single rank. Otherwise, as you say, it won't reach that speed using all the slots.

If you look at the first image posted by the user, there is a 4800 MT/s memory. I think that's the original one that HP puts in.As HP says, mixing memory modules causes the frequency to drop to 3200 MT/S. The user should use memory modules of the same speed and brand, to obtain the maximum of 4000 MT/s in dual channel.

[TzortzisG]

Surprisingly HP had a different Quickspecs yesterday from the one on its servers today. You can still see the previous version attached to my original post. Today's version of the document (8th revision) has a table that clearly shows DIMM1 or DIMM1+2 populated giving maximum system (RAM) speed of 4400MT/s. It was the same on the previous DDR5 ZBooks.

Editing this to add further details and a full explanation for anyone interested. This post on the MSI forum provides a screenshot from Intel documentaion: Titan GT 77 HX 13VI 128 gb DDR5 memory running only at 3600 (MSI forum). Link to Intel documentation: Processor SKU Support Matrix (Intel).

[emreakaydin]

Thank you for your help and support, and also for your time. I will be returning it because it does not provide the speeds like in documentation, in fact, it provides much less speed.

thanks @resistencia    @TzortzisG 

[resistencia]

You're welcome, but here's a link from Crucial that explains why capacity is better than speed. Of course, having both is ideal, but for a user, the difference in speed in applications is practically imperceptible.

Why Enough is Better Than Fast (EN) | Crucial.com