HP elitedesk 800 G2 sff - upgrade RAM to 64GB

[sheliak]

Hello Gentlemen, I would like to increase the amount of RAM in my HP elitedesk 800 G2 sff computer - its motherboard is: SP# 795970-002 No DPK; SP# 795970-602 W8 STD/PRO; SP# 795970-602 W10.
I bought two 16GB memory sticks - (Crucial DDR4, 32 GB, 3200MHz, CL22 (CT2K16G4DFRA32A)). I connected them as the instructions indicated, i.e. to "DIMM 1" and "DIMM 3" (two black sockets) and everything worked - the BIOS detects 32GB, everything was ok until I connected a 10GBe network card to the lower (last free) PCIe, then suddenly my 16GBRAM disappeared (the BIOS did not detect it). I played around with it a bit. First I pulled out the 10GBe network card - RAM came back (partial success, but I need this card), so I switched the RAM stick from DIMM 3 to DIMM 2 and I also got 32GB back.
Does anyone know why this is happening? Does the last lower PCI-e have anything to do with RAM?
Why am I asking? Since I would like to expand the RAM to 64GB (and someone here in this thread wrote that this computer will accept this amount of RAM), I was thinking about buying two more 16GB sticks - Crucial DDR4, 32 GB, 3200MHz, CL22 (CT2K16G4DFRA32A), but will it work in this situation?
Or maybe there are 2x32GB sticks that fit this computer?

Please advise and reply.

Thank you

[NonSequitur777]

@sheliak,

Welcome to our HP community forum!

Yes, your HP EliteDesk 800 G2 SFF can indeed be upgraded to 4x16GB of DDR4 PC4-17000, 2133 MHz, Non-ECC, UDIMM, 288-pin RAM sticks, as specified: "Memory data transfer rates of up to 2133 MT/s" and confirmed here amongst 9,000+ HP EliteDesk 800 G2 SFF Users:  UserBenchmark: HP EliteDesk 800 G2 SFF Compatible Components, where none of the 800 G2 SFF's RAM ran faster than 2133 MHz, even with the i7-6700K.

Point is, that in a perfect world, your 3200 MHz RAM should effortlessly down throttle to 2133 MHz, but that may not always be the case -perhaps with 4x16GB 3200 MHz RAM sticks.

In my opinion, if you must upgrade your desktop to 4x16GB RAM, personally I would try low-voltage, dual rank 2133 MHz RAM, such as:

SK Hynix 16GB HMA82GU6MFR8N-TF Dual Rank (2Rx8) 1.2V DDR4 2133

Samsung 16GB M378A2K43BB1-CPB Dual Rank (2Rx8) 1.2V DDR4 2133

And see if this will fix your issue.

Kind Regards,

NonSequitur777

[DGroves]

or better yet simply go to a memory specialist and get ram that is guaranteed to work on your system

https://www.crucial.com/products/memory

https://www.kingston.com/en/memory

[sheliak]

Thank you very much for your answers, but I was more interested in the problem of "RAM disappearing" from the system. Has anyone encountered such a problem?
When using all PCI-e or the last PCI-e x16, suddenly part of the memory disappeared. Or maybe it is the fault of connecting some specific equipment to PCI-e x16, which takes this part of the RAM or blocks it...

Could someone explain this to me? Why could this happen?
The memory chips I bought are also low-voltage 1.2V - that's what the specification says...

Thank you

Best regards

[DGroves · Accepted solution]

issues like you are describing usually happen when  a "SERVER" specific or a OEM computer model specific network card is used, if this is the case replace the network card with a model designed for retail usage