Dell Precision 5280 Desktop RAM issue.

Question

I am attempting to upgrade the RAM in a Dell Precision 5280 Desktop computer. The user currently has 1 - 32gb ddr4 stick of ram. They need it to have 64gb in total. I don't have another 32gb stick so I'm trying to install 8 - 8gb ddr4 sticks. Now matter the configuration or number of sticks that I have installed I get a pre-boot error LED code of 2 Amber and 5 white lights which shows invalid memory installed on the Dell website. I double checked the sticks I have. They are Samsung 1Rx8 PC4 2666 sticks which according to the parts site is correct, apart from the brand name. Does anyone have any suggestions as to why I can't boot using the 8gb sticks, but it boots normally if I revert it back to the single 32gb stick?

Thanks in advance.

JOcean · Accepted Answer

First of all I assume you meant a Precision 5820 as the 5280 does not exist. Now it also depends on the CPU as this line from the specs indicates:

● DDR4 ECC RDIMMs - Supported with Xeon W Series CPUs
● DDR4 Non-ECC UDIMMs supported with Core X Series CPU

So it depends on whether you are trying to use ECC or Non-ECC RAM specific to your CPU. Of course it is also possible that 8x8GB RAM modules are not supported.

CarlL · Answer

You are correct, I did mean 5820, sorry for the typo. The processor is Xeon W-2133, and the ram I was finally able to find the specs from Samsung, appears to be UDIMM. So based on what you've provided it seems like this cpu/ram combination aren't compatible, is that correct? The reason I ask is that I used the computer's service tag and then went to parts and accessories, then to ram, and pulled up the 8gb 2666MHZ, it lists the UDIMM as the ram to use.

Edit: regarding the number of sticks, I have also tried using only 2 and only 4 sticks following the user's manual for a guide as to which slots to use, I still get the pre-boot led error.

Again thanks.

JOcean · Answer

Crucial RAM here, only shows RDIMM RAM as compatible. Interesting that the parts and accessories page does not show that. But the Crucial page would seem to be in line with the spec page.

CarlL · Answer

The RAM that I'm using actually came from another Precision 5820 that my company has. It is in another location but I'm trying to have the person who sent me the RAM verify if that computer also has the Xeon W series in it. That is the only thing that I could see being a possible difference, but typically my company orders computers of the same model in bulk. So, I would think they are the same 100%. Will update when I get word on the other processor.

CarlL · Answer

It appears as though the 5820 in our other location does have an X series CPU in it. So it looks as though I'll just need to get my hands on some RDIMMs and try that. Appreciate the assistance.

JOcean · Answer

Happy to help out!

fjsp · Answer

Hello, I have a 5820 xeon w-2145 which says that they must be ram RDIMM ECC 2666 according to the manual. It had 16 gb ECC registered DIMM (RDIMM as I understand it), I recently upgraded its ram and took it to 64gb With ECC Unbufered ram (UDIMM) as I understand it, where two are DELL and the others are Kingston and it is operating fine. The Rams I had didn't work with the new ones, initially because the new ones weren't registered. Bufered and Unbufered cannot be combined in my experience. I hope it helps. Greetings.

Dylanear · Answer

You are going to need to use all ECC Registered modules I believe. They all need to be ECC Registered or maybe all non ECC, but certainly a mix of ECC and non ECC is not going to work well if at all. And ideally, you will do so in multiples of 4 modules to fill out a 4 channel memory bank. Using just one or two modules will have slower ram bandwidth than using all 4 channels as intended by the chipset/CPU. Ideally you want to use 4 or 8 modules and they should all match exactly in a bank of 4.

Anyone have a link to qualified RAM modules for the Precision 5820? I can't seem to find one searching. I have 4 x 8GB ECC Registered 2666 modules in the first bank. I'd like to populate the second bank of 4 with 16GB (32 + 64 = 96GB) or maybe even 32GB modules (32+128= 160GB).

Dylanear · Answer

fjsp wrote: 'Hello, I have a 5820 xeon w-2145 which says that they must be ram RDIMM ECC 2666 according to the manual. It had 16 gb ECC registered DIMM (RDIMM as I understand it), I recently upgraded its ram and took it to 64gb With ECC Unbufered ram (UDIMM) as I understand it, where two are DELL and the others are Kingston and it is operating fine. The Rams I had didn't work with the new ones, initially because the new ones weren't registered. Bufered and Unbufered cannot be combined in my experience. I hope it helps. Greetings.' - - ECC RAM comes in buffered/registered and unbuffered/unregistered. And then there's regular RAM which is not ECC nor buffered/registered. Often ECC and Registered are used interchangeably, but that is not correct. I never once ran into ECC RAM that wasn't also Registered until I got an AMD Ryzen system a year ago, those can use ECC RAM, but it must be Unbuffered/Unregistered. I don't think it's advisable to use ECC Unbuffered Ram in a Dell 5820 at all. If you use ECC in these machines, it should be Buffered/Registered. I could be wrong, but that's my take on it.

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Dell Precision 5280 Desktop RAM issue.

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