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- HP Z840 upgrade Xeon 2680 V4 issue ram

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11-11-2023 03:03 AM
Hi,
I ask for help, I have an HP Z840 with 2 Xeon E5 2620 V4 and 64 GB ram.
I tried to install 2 Xeon E5 2680 V4s and when I turn them on I always get 5 beeps which would indicate RAM problems.
The tests I did: all 2 new CPUs placed individually on the CPU0 socket work so the CPUs are not faulty.
The RAMs all placed on the CPU0 sockets work and are therefore not faulty. I put the RAM back where they were before and re-installed the 2 Xeon E5 2620 V4s and everything started working well again.
So by exclusion all the RAMs work, the 2 Xeon 2680 V4s work, the memory controllers work otherwise they wouldn't even go back to the Xeon E5 2620 V4s. Basically everything works except when I have the 2 Xeon E5 2680 V4s mounted together.
What am I missing?
Help!
11-11-2023 11:19 PM
are the v4 2680 cpu's RETAIL or QL pre production?
do the cpu's "SPEC" codes match?
do you have the optional 1200 watt power supply?
you must have the upgraded power supply, the stock 850 watt unit will not reliably boot/power the system when two 120 watt cpu's are installed
what speed is the ram? the 2680 memory controller supports DDR4 1600/1866/2133/2400 ECC Registered when using 64GB or more ram
memory errors on a z840 are almost always due to
improper dimm placement (wrong socket order)
incorrect ram modules such as non ECC when ECC is specified or using low powered "L" suffix ram
mismatched ram such as mixing 2rank and 4rank modules in a bank, or mixing ecc/non ecc ram
a actual defective ram module
a defective ram socket
bent pins on the cpu socket (only applies to cpu's with embedded ram controller)
https://www.manualslib.com/manual/928210/Hp-Z840-Workstation.html?page=22
11-12-2023 04:53 AM
CPU RETAIL both SR2N7, NO QL pre production
I have 1200W power supply
Ram speed 2400 DDR 4 ECC
Ram modules and ram socket are OK, are healthy, work well with Xeon E5 2620 V4
When i use the CPU 2680 one at a time on the CPU 0 socket and all 64GB ram everything works fine and you can see all of the ram so i think that the Xeon E5 2680 V4 "digest" this ram well otherwise it wouldn't work, right?
If i just change the CPU's and don't touch the ram layout it should work, right?
If i had bent pins it shouldn't even work Xeon E5 2620 V4 or not?
If i have bent pins could 2620 work and 2680 not?
If i have mismatched ram such as mixing 2rank and 4rank modules in a bank, or mixing ecc/non ecc ram could 2620 work and 2680 not?
I really appreciate your input, thanks!
11-12-2023 05:16 AM
current cpu's integrate the memory controllers on the cpu die
they also use a dedicated bus to talk to multiple cpu's via the cpu's embedded "QPI" links
i suspect that you have a non functional "QPI" link between the two cpu's (IE-one or both cpu's are defective)
mark one cpu with a mark somehow, reinstall cpu's and test, if problem occurs swap cpu's to see if the problem goes away or changes
the fact that the other cpu's work absolves the motherboard itself from the problem you are having
11-12-2023 06:11 AM
OK, but when you say " mark one cpu with a mark somehow, reinstall cpu's and test, if problem occurs swap cpu's to see if the problem goes away or changes " do you intend to try both CPUs at the same time ( in this case i should have a third CPU ) or only one at a time?
Thanks again!