Optimal RAM Specs for G5 SFF

[Barb00ts]

I'm making myself a hard time out of choosing replacement memory modules for my G5 SFF. I was not aware of the BIOS limitations, and reading the HP "maintenance manual" for the G5, the memory requirements are extremely strict. The aspect that concerns me most is that it states CAS19 only. Will this machine not work with, or take advantage of, CAS16 sticks?

I "understand" the following:

- no ECC or buffered

- matching pairs

- dual rank only if 2x slots used

My questions:

- will CAS16 be accepted?

- will CAS16 be utilised, or will it still clock at CAS19?

- will sticks faster than 2666MT be accepted, and if so, is that determined by whether they have a suitable profile programmed?

Perhaps I'm getting too caught up on CAS16. If users have quick memory modules to suggest, I welcome opinions.

Cheers!

[NonSequitur777]

@Barb00ts,

Welcome to our HP User Forum!

One of my favorite/most recent upgrade projects happened to be an HP EliteDesk 800 G5 SFF: Solved: Upgrading HP EliteDesk 800 G5 SFF Part II - HP Support Community - 8720291.

Long story short: purchase dual rank RAM, such as 2x16GB Dual Rank (2Rx8) 1.20/1.35V, Timetec DDR4 PC4-25600, 3200 MHz, Non-ECC, Unbuffered, DIMM, 288-pin (p/n: B07QRVNB26).

And yes, RAM on this desktop cannot run faster than 2666 MHz.  Therefore, the aforementioned 3200 MHz RAM is down throttled to 2666 MHz.

Kind Regards,

NonSequitur777

[Barb00ts]

Thanks for jumping onto my question... I had seen some of your informative posts and hoped that you would share your learnings. I appreciate the memory model number suggestion, and will quite possibly go that way.

I would have liked to bargain-hunt someone's hand-downs, but there isn't a lot around and with a somewhat fussy BIOS it could be frustrating.

Many thanks again.

[NonSequitur777]

@Barb00ts,

You are most welcome!

-To be honest, my 2 x 16GB Timetec purchase was primarily driven because Amazon-US offered a good deal.  This RAM doesn't 'look' like fancy heatsink/RGB-dressed gaming RAM, but then again, that is mostly just fluff anyway.

Good luck!

Kind Regards,

NonSequitur777

[Barb00ts]

 I am still trying to understand faster memory in the context of this platform @NonSequitur777, for example with your 3200MT/s. I have studied your upgrade post further and noticed that your new modules have a 2666MT/s JEDEC profile, with CAS 19. I have received the impression that without a profile to match current BIOS settings, or the ability to change BIOS settings, a higher-speed memory device would revert to the DDR4 base DRAM frequency of 2400MT/s. So you researched well, as I have not found Timetec to offer particularly comprehensive data on this memory module.

Do you think that if your modules had a JEDEC profile of 2666MT/s with a CAS of 16, that they would run at that?

[NonSequitur777]

@Barb00ts,

To be honest, I don't know the answer to that. Like many of your and my upgrade efforts, it's been a trial-by-error approach, as there is not a whole lot of information available online going where few (if any) have gone before.

Kind Regards,

NonSequitur777