Memory compatibility issue HP Z840 Workstation

[Wentz]

Hi, I recently bought a refurbished HP Z840 with 128GB memory. The memory modules are 4x 32GB Micron MTA36ASF4G72PZ-2G3B1II, PC4-2400T 2Rx4. I wanted to upgrade it so I bought another 128GB of the same brand with the same features and almost the same product code - Micron MTA36ASF4G72PZ-2G3B1MK.

Unfortunately I got memory error (5 long beeps) and the system did not boot. I really did not expect this because I thought the modules were almost identical. I am aware that HP is not Lenovo, but still, when I look at the general features, they should work. I tried to boot again with the "Lenovo" memory only and got the same memory error again.

I would like to understand where is it going wrong:

1. Is it because the memory I bought is simply not compatible with my HP Z840 Workstation?

2. Is it possible that HP is accepting memory with only HP's "own" security sticker? ... and if so,

Is it possible to disable some security feature in the BIOS so that I can still use these memory modules (they were not cheap!)

We all learn from our mistakes and I would really like to know where did things go wrong in my case.

Please let me know.

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[old_geekster]

@Wentz , welcome to the Community.

Here is the Maintenance and Service Guide: http://h10032.www1.hp.com/ctg/Manual/c04823811

On Page 20 is a list of compatible memory and instructions for installing it.  Also, here is the Product Specifications: https://support.hp.com/us-en/product/hp-z840-workstation/6978842/document/c04505606

Look at the section titled "Memory" for the compatible modules.  The specification that I don't see in you pictures is the ECC and it shows DDR4-2400T; not DDR4-2133.  There is a lot more information in the both guides to help you in the future.

Please click the Thumbs up + button if I have helped you and click Accept as Solution if your problem is solved.

[Wentz]

@Old_geekster 

Thanks for your replay!

I don't think that this is the problem...

Both memory modules (The HP "brand" and Lenovo) are ECC registered memory. I've checked this carefully before I bought it.

The memory modules (HP branded - photo 1) are indeed 2400 MHz, but they operate @ 2133 MHz due to the limitations of my cpu's (2x Intel Xeon E5-2667 v3). These modules were in my workstation when I bought it and it works perfectly with them.

That's why I bought memory which was similar with what I already had. 

It must be something else..

[DGroves]

a quick test, note the slots your current modules are in, then remove them and insert your new modules, i suspect they will boot the system. if so the issue is proper slot placement for your other 4 modules

[Wentz · Accepted solution]

@DGroves,

Thanks for your response!

I've tried this already couple of days ago and it didn't work. Got the same memory error beep code...
Then I tried to load just 1 module of each kind (1x HP and 1x Lenovo) per CPU, just the minimum. Slots 1 en 2 as recommended.
And it worked! The system booted with a weird POST error (photo) message, but once Windows loaded, everything was fine.
Now I knew at least that this memory was compatible with my machine.

Once it worked this way, I replaced the working Lenovo module with another one of the same kind.  Still, with only 2 modules.
And I got memory error again!
And again with the next one.
And again with the last one.
I even tried to place 3 HP modules and 1 Lenovo.
It worked again. With the first one I tried.
Not with the other three. They all kept on giving me memory error.
The only thing I could conclude was that 3 out of 4 purchased memory modules were defective.
It was used memory, fortunately an eBay purchase, so I'll be able to return it.

This never happened to me before in more than 25 years of experience.
I never had a defective memory module before and now suddenly 3 out of 4!
Quite bizarre!

Thanks to everyone who took the time to read, think and comment my post.
The problem is solved.

[old_geekster]

@Wentz 

You are welcome!  Glad that you solved your problem.