XPS 8940, no boot with 128GB ram

If i put the orignal 64gb (32gb x 2) ram back into the same color slots, it wont boot anymore.

Also how should i put the 4 ram sticks from each set color wise? 

You may have 64GB of memory . . . but you are not running dual channel if you are seated it different color locking tabs. The Setup and Specifications document indicates max memory speed of 2933 MHz . . . not sure if a subsequent BIOS release has improved on that speed.

In addition to disconnecting power and removing the CR2032 coin cell battery, you should press and hold the power button for 30 seconds to discharge any residual power. Then put all 4 RAM modules securely seated and locked in their slots, and try to get a successful boot.

Does PC boot with just the 2 new modules installed, and then you clear BIOS by removing the battery and pressing/holding power button on PC for ~30 sec, before reinstalling the battery?

Others have found when "mixing" module pairs, the XPS 8940 prefers having the matched pair of modules in slots with mismatched retention clips. No explanation for why that works, but lots of users have confirmed this unusual finding...

EDITED for clarity...

You have to clear CMOS first, then try to boot.

If the RAM modules are identical . . . it should not matter which one is where.

I have the motherboard model number: OK3CM7

And the originally motherboard clearly supported 128gb even when i ordered it, i think the issue was that some how trying to install more ram caused it to fail. Because originally i had a 32gb crucial ram module in the two white ram slots first and then after i tried all this, the 1, 3 white/black ram slots refused to work at all even if i put one ram module in it and boot it, it wouldnt boot. I even tried to put back the ram in the original two white slots and it didnt work because one of the white ram slots wasnt functioning, along with the black one next to it. So i had to use the remaining 2,4 white/black ram slots to make it boot but it was single rank as another commenter commented. But getting this new motherboard i am at 128gb and at dual rank. Something corrupted the bios/motherboard because if anything was plugged into the 1,3 the computer would not boot, even if i had ram modules in 2,4 or if i didn't have anything else plugged in. 

Please see my specs below. 

Also is there a benefit to having this newer OK3CM7 motherboard? I think it still only supports PCI 3.0 correct, not PCI 4. and I can't upgrade the processor to 11th gen correct? 

Thanks!

Hard to tell the real reason at this point?

There were a few Motherboards released for the 8940:

=================

Motherboards =
KV3RP Foxconn 02012PQ00-600-G, Released July 9, 2020
2W4W1 Foxconn 02012TA00-600-G, Released December 1, 2020, Brazil only
F1H92 Foxconn 02012YJ00-600-G, Released March 15, 2021, Brazil only
427JK Foxconn 02012VY00-600-G, Released March 15, 2021
K3CM7 Foxconn ??, Released July 14, 2021

================

3 not including the Brazilian one. I suspect the first one supported the 10th Gen Intel as some were shipped with 10th Gen I recall and the FAQ for the 8940 shows that too.

Quite possible one of the boards did NOT support 128GB.

I assume the new one you got was one of the last two? MSINFO32 from a CMD prompt will show you the board you have:

Mine is BaseBoard Product 0427JK for instance.

I had the last one in too, but Dell replaced that with the older one when I had a Video problem. Suspect you now have the same one I do?

Interesting answer there....

First think I noticed, you have the 10th Gen Intel. Probably got the 8940 when it first came out, or shortly after they did? The did switch to 11th Gen Intel later, probably Mar. of 2021?

If so, I'd assume you had the 1st board? The later 2 were on the 11th Gen Intel CPU's I think?

Possible a pin was bent or shorted out putting in the last DIMM's?

Matters not, the problem is solved.

Dell tried to get me board you have, took 2 tries, and they were not in stock so they sent me the one I had (and have now). One try the first board was sent I couldn't not even boot with it, probably a bad board (most repair/replace parts are reconditioned) and the one I had had to be put back in to allow boot.

From what I understand, the last two boards (according to Dell Support when they were trying to get me the last board to test with) and the only difference is the sub-vendor and what you have is the latest now. Interesting that it too supports the 10th Gen Intel CPU's?

Wondering though if you ever had the lock-ups other Nvidia users have? Only resource to recover the system is to use the power button to reboot?

I've seen a lot of reports of people not having the problem, and I'm wondering if it is the Intel Generation of chips that matter?

I dont have any issues with the xps 8940, what do you mean by lock up?

Also yes i oet it right when the xps 8940 came out so i have the 10th gen, i believe it was September 2020. I looked it up after I posted what i posted and realized that the motherboard does support 11th gen but after doing some research it seems like going from a intel 10th 10900k to a 11th gen 11900k isnt much of an upgrade so i think ill stick with the 10900k now. I might upgrade my GPU to a 3070 though, assuming it possible from my 2070 super that came with the computer

It is hard to imagine how adding 2 RAM modules could ruin a motherboard . . . but glad to know you got it working!

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@Socom Master wrote:

I dont have any issues with the xps 8940, what do you mean by lock up?

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Many 8940 owner's with BIOS V2.4.0 or later and have a discrete Nvidia card installed and being used have experienced RANDOM lock ups of the system. NOTHING works. When it happens the screen will not update, not even the System Clock on the right side of the Taskbar (Systray). Mouse will not move, keyboard does nothing. In some instance, the PC will not come out of sleep. System is totally locked up (some have called it a 'freeze' or 'frozen'). However, it seems many do NOT have the problem? If one switches to use the Intel HD adapter there is no problem.

With BIOS V2.4.0 if one went back to BIOS V2.3.0 there was no problem either. Clearly BIOS related and one must have an Nvidia card they are using. AMD cards, and 8930 and 8950''s with Nvidia cards do not have the problem either? Only 8940's, but NOT all of them.

Never been able to PIN DOWN why not all 8940's with an Nvidia card either? Your h/w configuration might be a hint? Windows 10 Pro and the 10th Gen Intel. All others with Windows 11 (both Home and Pro) and 11th Gen Intel CPU's (all versions) are reporting the problem.

So your answer might help understand why not all 8940's experience the problem.

That said, on BIOS V2.10.0, like I am on and did 'have' the problem, it is holding up quite well. Rarely will I have a lock up, and the last 2, almost 1 month apart, were during the Install via GEForce Experience of the latest Nvidia driver for my RTX2060. I'll do the new installs manually next time as I think the GEForce Exoeriance could be part of the problem.

If you have an S.E. version of the 8940 you might be OK upgrading. The Nvidia RTX3070 does draw more power and generates more heat. Check the forums here for some that have made that upgrade. Might want to look here, https://gagadget.com/en/graphics-cards/geforce-rtx-2070-super-vs-geforce-rtx-3070/ but Dell when they include Nvidia cards they are made by someone else of course. For the 8940 according to the FAQ this is what they used, "KX61M MSI GeForce RTX 3070 8GB"

Dell though might not provide the Retail MSI card? My RTX2060 is provided by MSI as well, but it does NOT look like the Retail one MSI sells. I have 2 large fans on the card, MSI's has 3 smaller one. Suspect my card will draw less power too. Although the 3070 is not drawing much more than 2% power more, if you get a retail card it could be more than the Dell supplied 2070S?

Some reviews indicate the gain might not be worth it switching as well.

By the way. the 8940 only has a PCIe 3.0 Bus, and the RTX3070 can use the 4.0 Bus it seems. Also, power connectors are different.

Of course, that data is for RETAIL models, Dell's could be different as they do put the 3070 into 8940's?