[hvem10]

I am configuring a workstation with 2 Xeon-E5-2687W.
I want to use the DDR4 2400 MHz memory, but my hardware supplier says he can not guarantee it works with the motherbord, ASUS Z10PE-D16 WS.

In the specs for the motherboard it says it supports the 2400MHz memory, but there is a note that says, *1 Only 2133MT/s@1DPC

So now I am confused, anyone that can help, does the motherboard support 2400MHz memory and what does the note mean.

Thanks,
SJ

[flotus1]

I was trying to get more specific information about the same topic lately. I ended up choosing the Supermicro X10DAX instead for various other reasons.
Interestingly, I found the exact opposite: DDR4-2400 is only supported using one DIMM per channel (or using LRDIMM which is not really an option for me). I asked Supermicro support about this and came to the conclusion that as soon as you use more than one (R)DIMM per channel you end up with a maximum officially supported memory speed of DDR4-2133. I don't know if you can try your luck and increase the frequency manually, support people really avoid answering this kind of question.

Edit: I think it is a bit different with the Asus mainboard. The specifications read

16 x DIMM, Max. 1024GB, DDR4 2400/2133/1866/1600 MHz RDIMM, LR-DIMM Memory *1
*1 2133MT/s@1DPC only

So the DDR4-2133 restriction might apply to LRDIMM only. And the use of LRDIMM could be restricted to one DIMM per channel maximum.

Btw: there is a forum section dedicated to the motherboard you intend to buy, maybe you will get a better answer there: http://www.overclock.net/t/1579548/a...-owners-thread
Although looking at some of the latest posts seems to confirm what I could find out so far: the maximum memory frequency only works with one DIMM per channel. According to the information from supermicro, this is regardless of the amount of ranks per DIMM. So even with single-rank DIMMs you will be limited to DDR4-2133 maximum as soon as you have more than one DIMM per channel. Consequently, I would recommend buying 8 DDR4-2400 dual-rank DIMMs with the capacity you need in the first place. Upgrading memory capacity later with additional DIMMs will reduce memory speed.
And you can try to get an answer from Asus support directly. But this is one of the reasons I went with Supermicro instead.

[hvem10]

Thanks, for your detailed answer.
I see it is a bit tricky. For now i will be stuck with the ASUS board, but will investigate the supermicro.

The CPU's each have 4 channels, so if I select 8 memory block, say 8x8GB or 8x16GB, I could be lucky that the DDR 2400 will run a max speed. Is that correct understood ?

[flotus1]

With only 8 DIMMs DDR4-2400 should work anyway. Use dual-rank DIMMs for maximum performance. Be aware that only the v4 version of your CPU supports DDR4-2400.
If you want to be on the safe side use memory from the QVL: http://dlcdnet.asus.com/pub/ASUS/mb/...374.1478632810

Here is a snapshot from the supermicro manual concerning this topic.
sm_dimm.png

[hvem10]

I managed to get the system.
But I am not satisfied with the performance. I just made a simple comparison on a CFD case, where the 2x2687W v4 (24cores) is only around 25% faster than an older system with 2670 v2 (20cores)

There must be something wrong. I have disabled hyper threading, but I dont know how to trouble shoot this. The 2687W machine is running with windows 10 and the 2670 with windows 7.
I would appreciate any hints

[flotus1]

25% shorter simulation times are not that bad.
To see if there is something wrong you have lots of options. Let me name just a few:
Use software like CPU-Z and HWinfo to check the parameters of your system (temperatures, frequencies, cpu throttling...) while running a CPU stress test for a longer period of time, e.g. with Prime95.
Run independent benchmarks for CPU performance (e.g. Cinebench) and for memory performance (Aida 64).

Which company did you buy from? Or if it is not one of the large vendors, what are the exact components of your system?