09-15-2019 09:37 AM
Please could someone tell me if the earlier model (2014) of Z840 could use also E5-2600 V4 series CPUs.
Could It be possible to use both DDR4-2133 and DDR4-2400 ECC togeher?
HP Z840 E5-2643 v3 x2 32GB Quadro M4000 Win 10pro x64
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09-15-2019 02:13 PM - edited 09-15-2019 02:32 PM
I'd say yes.... I'm running a E5-1650 v4 in a Z440 that was built in 2014 and which is also running the 2400 memory, and that all works fine.
I'd get a later Z840 Quickspecs for reference, HERE.
Go to page 3 and 4..... I think you'd only want a HP-approved v4 processor from that group, and only ones that have 2 QPI links, and only ones that can run the 2400 fastest memory. Mixing 2133 in with 2400 memory would slow the processor and 2400 memory down to 2133. That is 12 of them listed there, ranging from quad cores on up. Not many of those out there on eBay, used, cheap.......
This is the Intel Ark page for the E5-2643 as an example, showing the presence of 2 QPI links, HERE.
A single QPI link processor is fine for a workstation like the Z440 that only has one processor socket or a dual socket motherboard that will only be running one processor. In contrast, the processors for a dual processor workstation must be matched and must each have dual QPI links.
I have never read or heard of there being a problem converting to more advanced HP-approved processors in the ZX40 family, but HP does not support that. Their stance is that they support adding a second identical processor to the one that came with the box if the box and the other processor is built to do that. But, HP does not officially "support" upgrading to another processor. We do that, and self-support.
09-15-2019 02:37 PM - edited 09-15-2019 02:38 PM
while you can mix ram speeds there are some things to be aware of
first, the z840 supports two different ram modes UMA/NUMA which comes into play if using 2 (or more) CPU's and UMA mode is the bios default
Unified Memory is a single memory address space accessible from any processor in a system. IE- each cpu can see/use the other cpu's ram/memory banks
Under NUMA, a processor can access its own local memory faster than non-local memory (memory local to another processor or memory shared between processors) IE- each cpu only sees it own ram banks
each bank of ram must have all the modules be the same speed
the system will run no faster than the slowest ram bank
numa mode with mixed ram is not recommended, and HP also does not recommend mixed ram speeds although it does work for most people/uses
09-15-2019 06:07 PM
I'm very glad.
I asked you because the earlier model of Z820 supported only E5-2600 V1 while the later supported also E5-2600 V2. From your experience it will be possible to assume in the case of Z840 instead there is not difference between 2014 and 2017 model at least about the specifications of the motherboard.
Thanks to your advice I'm now ready to upgrade.