I suggest you remove the troublesome and incompatible memory. Return system to its original factory memory configuration, with just the one OEM DIMM.

 That should take care of your memory trouble, and it might take care of the other Long Posting problem as well.  Do not try to fix both problems at once .

Does your machine pass Dell ePSA Diags (outside Windows)?

That's confusing bit. The system works just fine with the purchased memory OR with the OEM memory. It's just that they don't work together. But if there's only one stick in place - it runs perfectly. 

Also, using only the OEM memory module makes no difference to the POST time. Machine seems to pass Dell ePSA as well..

the PC never once tested as  minimum system and all that is going on here is the DDR witch hunt.

My post was too long, here is the short version, (run only matched RAM in your PC, and certified at 32GB.

You don;t want to and that is clear, INTEL tells you in the data sheet clear as day that is a limit,  and you dont want to believe it,

now we learn you tried 5 motherboards and on not once did the tech, do a strip down test?. with full ram added 1 by 1, (a.k.a,  reducing to a minimal system and is done in every shop, SOP, !)

we strip all PCs down first.  (there is a post online from geeksquad guy(back room pro) retired and that is the top of his list)

why? because it  MUST BE DONE, (not 5 motherboards first, NOT EVER)

The memory must be certified, for sure at max ram size.

Kingston sells them but nobody wants to use the correct ram, and as Intel tells you clear as day (it's there logic)

it warned you not to MIX types or the system will be unstable. (or dead or ? well not normal)

but allas the GPU is bad.

OK THE LINK, GEN 8

 INTEL.COM, Scroll down to gen 8

data sheet 1.

page 19 and 20

note that DDR runs in 1 channel and 2 channel modes and are not the same rules ! (ok to see if ram is dead but never to see if all 4 work as a   TEAM)

SKU means the makers of the STICK and their model number of the stick (and even bar coded)

if you read this carefully it tells you not to mix STICKs types (logic) nor SKU,

that means , buy them all as SET , matched, if down time huge, is not wanted. (at the least !)

page 2 next.

if you do not understand the rules of logic  above iniside your CPU. MMC>

then please just buy matched sets of ram. (sell the old ,  and buy NEW in SETS, with matching SKU if savvy.

the above, only covers hard logic failures, not BIOS limits or MOBO PCB band width limits

nor does it cover, bus  capacitance rules (violations) and such.I do not have a TRUE DELL SPEC, they do not tell that, nor do QVL lists of DDR4 here.  leaving only  2 paths, use qualified RAM, or spend months finding mixes that work, using the logic table shown above.

ok it is gen 8 CPU,

the techs are clueless because they do not understand, DDR logic, nor do they understand the limits of unbuffered RAM.

nor why just the CPU alone logic (MMC) memory management controller inside has rules, hard fast logic !

Gen 8 Chipset Intel Z370 chipset,

the GEN8/9 uses the same rules of the logic above.....

if you read the core gen 8 data sheet , on DDR4, it flat tells you not to mix logic types, clear as day

here is what that states

• The Intel data sheet on your CPU clearly stated,"not to MIX,  rank, SIZE GB, Speeds, Density, or Timing spec, nor or chip organizations" or it clearly says," it will fail or be UNSTABLE ! (hard proof here at Intel.com)
  
• Intel even tells you in their great data sheet "not to mix even SKU's " this is the VENDOR name on the STICK the stick or more  clearly do not mix vendors or vendor model numbers on sticks. Only buy matching FULL SETS.

if you need the link to the datasheet at intel.com  and page numbers stating that CAN DO.

the MMC does allow FLEXRAM rules,  for example  size of sticks not matched, on 1 channel A or B.

nobody does that  like this.

B1C-A (bank 1 channel A) 4GB (flex rules lower it to 2GB to match below)

B1C-B   2GB.  (use 4 not 2 but 2 WINS) see?

this is allowed, but nobody does this, waste of DRAM.

Buy your RAM is full sets, sell the old ram, and buy certified RAM, (DDR4), FOR THIS PC.

IT  LOOKS SIMPLE BUT SORRY DDR IS NOT .

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@Refractor wrote:

1. The system works just fine with the purchased memory OR with the OEM memory. It's just that they don't work together. But if there's only one stick in place - it runs perfectly.

 

2. Also, using only the OEM memory module makes no difference to the POST time.

3. Machine seems to pass Dell ePSA as well..

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1. I don't care.

Please install the original OEM 16gb Memory DIMM (only). Leave it that way until a week after POST-ing problem is resolved. I know you don't need 32gb right now.

2. OK

3. Good. Then about a 90% chance your hardware is actually good.

Have you tried disconnecting all your USB devices? Do you have anything else strange connected to the system-bus ? Systems usually do this when they are having trouble enumerating all the available system devices.

1. I do need the 32GB. Else I would have just left it as is with the stock 16GB. As already mentioned - only the OEM 16GB is installed right now. POST issue remains.

2. Yes. I've tried with everything except the Display plugged in - makes no difference. I have also tried removing the stock NVMe SSD - makes no difference to POST times.

the problem is only 1 , 32GB  (we later learn it just a bad GPU card)

why not run a set of kingston  DDR4, qualified RAM ?

you failed to buy and use qualified certified ram,  you mixed types, and Intel told you not to.

The intel CPU MCC rules must be followed, DELL nor anyone can change the logic inside the CPU MMC

that is my only point, if not clear,  sorry, but there are many DDR sticks that do not work as a TEAM.

that newer processor also uses a newer , adaptive lower memory , PCI-E usage areas, and if the wrong DDR is use or mixed that too can  get confused.  You really need to learn to use only certified RAM.

my post is not how to fix your PC only the add to the DDR witch hunt here,  not doing all tests. there are lots of tests. and this

the new ram rules are more complex , here they are at G4 UP. try to know that Adaptive ram needs RAM that supports Haswell spec. too. not just the mixing of RAM types bad but this.

see this RED ARROW , if you use the wrong RAM not Gen4 certified,  the PCI cards can fail. see why>?

Gen 4 up has this so DOES YOURS

Haswell Gen4 up

Savvy, I do appreciate the help but unfortunately I'm not able to quite follow your posts. I'm guessing you're saying that the module isn't compatible as a pair?

Refractor,

Below is the Dell OEM 16GB memory stick that we shipped on your Aurora R7 =

RMWRN XMP 16GB, 2933MHz, DDR4, 2Gx64, 8K, 288 pin, 2Rx8, Dual Rank, Unbuffered, 1.35v, Non-ECC
Kingston XRMWRN-HYA
Kingston XRMWRN-MIE

Any (not validated by Dell) retail memory has to match all of those specifications.

Mixing Speed and Rank and Density etc is not supported.

Ram goes into interleaved slots so the White Ears are first bank and Black ears are 2nd bank.

Thats 1 then 3     2 then 4   NOT 1 then 2 then 3 then 4.

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@Refractor wrote:

now taking almost 20-25 seconds, before the BIOS splash screen(Alienware logo) shows up - before that it's just the no Post black screen. Any idea why this is the case? Can't find any info anywhere.

 

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I just checked for you.

On my Aurora-R6, (with Dell u2717D LCD on DisplayPort) the Alienware logo appears in about 4 seconds ... after pressing the power button to turn it On..

I'd say total boot-time (to a usable Windows desktop with all 100+ processes loaded) ... is under 30 seconds total. Once a day, that's not too bad. 

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@Refractor wrote:

1. I do need the 32GB. Else I would have just left it as is with the stock 16GB.

1b. only the OEM 16GB is installed right now.

1c. POST issue remains.

2. Yes. I've tried with everything except the Display plugged in - makes no difference.

3. I have also tried removing the stock NVMe SSD - makes no difference to POST times.

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1. Whatever. You can't mix DIMMs dude, so why not install the Dell one?

1b. Thank you sir. And you are sure it is in the correct slot?

1c. Understood.

2. Good and Understood.

3. Really? You dropped a recent SATA-SSD in there (only) , and installed Windows-10 on it?

If anything, I would try with only the bootable NVMe-SSD connected ... as the only drive.

I think you misunderstood. For me it's currently taking close to 30 seconds just for the Alienware logo to show up. Another 30 odd post that for windows to be ready to use. So definitely something stalling the boot up at a BIOS level.. 

3. I meant what you've mentioned only. This is with the stock NVMe which has the Windows on it. Dell is replacing the motherboard, so let's see what happens to the POST post that.