Upgrade Z4 G4 Xeon Workstation - Processor and Memory Upgrade

[aszalacinski]

I have a Z4 G4 Workstation, now running Windows 11 Pro, which I purchased in 2018. I am very happy with it but didn't max out it's capabilities when I purchased it. I purposely purchased the Z4 so I could upgrade the processer down the road.

The HP documentation contradicts itself and the help/search doesn't align with the documents. I am not experienced in these deep details of CPU upgrades and learning so any assistance would be appreciated.

The computer motherboard is the HP 81C5 MVB. My current processor is the Xeon W-2125/4 Core that uses the LGA2066 platform. I also currently have 24GB of memory but want to know what the max memory configuration is as well.

1. Where can I find documentation on the HP 81C5 MVB motherboard? Searching the HP site and the internet doesn't provide any insight.
   
   
2. Can I drop in any modern LGA2066 chip, something developed in the last year? Or does it need to stay on a legacy chip that was of the same chipset? 
   
   
3. Does it need to stay Xeon? Or can I go I-9?
   
   
4. Does the particular CPU choice have a limiting factor on the amount of memory?
   
   
5. HP docs and other tools that scan my setup show that between 512GB or 254GB can be installed. So which is it? Why the difference?
   
   • For instance, if I got to Crucial and look for the specs of my computer it states I can install 512GB but doesn't provide state 64GB chips are compatible, even though when I purchase this system, the 64GB chips were. I suspect this is just confusion of the custom setup of the machine.
   • If I look at the spec sheet from 2018, 64GB chips are specified with the Xeon processor as long as a memory cooling block in installed. I have the cooling block.

Appreciate the assist! 

-Aarron

[erico · Accepted solution]

The Quikspecs document at the link provides more information than you have found so far.

https://h20195.www2.hp.com/v2/GetDocument.aspx?docname=c05527757

There appear to be two different motherboards for the Z4 G4 workstation. One has the X299 (Intel® Core™ X-series Processors) and the other has the Intel C422 chipset (Intel® Xeon® W Processor Family).

With that said, you can't put an Intel Core X series processor into a socket of the  board with the Intel C422. If you want to upgrade it will need to be one of the Intel® Xeon® W Processor Family processors that is listed in the Quikspecs document.

They each also accept different memory types and that is also dependent on the OS that is installed. The XEON W processor family needs DDR4, RDIMM (Registered), ECC  memory and the Intel Core X-series processor board accepts only non-ECC unbuffered DIMM. The motherboards and chipsets are also very specific about the memory module load order.

[aszalacinski]

Awesome! Thanks for clarifying Erico and pointing me to the newer spec... much appreciated!

[noreennaina]

Your HP Z4 G4 Workstation, acquired in 2018, offers the potential for processor and memory upgrades. The motherboard, HP 81C5 MVB, is not extensively documented on the HP site or elsewhere. While LGA2066 processors can be upgraded, compatibility with recent chips may depend on BIOS support. Xeon or Core i9 chips might be options, but check compatibility thoroughly. CPU choice generally doesn't significantly impact memory limits, which could be 512GB or 254GB according to HP's contradictory documentation. 64GB chips were compatible with your Xeon processor in 2018 and should still be, especially with the memory cooling block you possess. It's recommended to consult HP's official resources or reach out to their support for precise guidance on your upgrade options.

[erico]

@aszalacinski 
You're welcome!