XPS 8940, crashing issues since December

I came across this topic:
XPS 8940, random freezing – Seite 21 - Dell Community

We have 2 8940/i9/3060Ti and only one have the lock-up problem.
Both are identical except amout of RAM 32GB vs 64GB
and one machine is extended with some HBA DC614 to support 4 more SSDs.

I checked my machine (this one makes no problems)
Mainboard is 0427JK  A00
Firmware on both machines is 2.7.0 today upgraded to 2.8.0

I also opened a topic here:
https://www.reddit.com/r/Dell/comments/vvuky5/sudden_freezes_on_dell_xps_8940_with_windows_11/

Is DELL currently investigating this issue? Can't believe that this is uncoveredfor such a long time.
On some days the other machine lock-up to 2-3 times.per day. It is frustrating so switch off the machine, when documents are open and reworked but not saved.

I also believe that downgrading the bios is not a solution - so no Kudos for this one.

"Is DELL currently investigating this issue? Can't believe that this is uncoveredfor such a long time."

Well, anyone that works for Dell has NOT posted any information on this. If you contact Support they only do the usually stuff, re-install Windows and drivers, replace h/w, etc.

"I also believe that downgrading the bios is not a solution"

Correct, it is a work-around. Don't like losing all the possible fixes and CVE's fixed either, but I don't like losing work or program settings either. I'm on V2.8.0 now as it happens less frequently, only twice so far since released.

I've lost on lock-ups, more than work in progress... I've had a few time programs lose their settings, depends what is open and in the process of being written at the time of the lock-up. If the 'right' Windows file is the one that is corrupted, you might even need to re-install Windows.

See, part of the problem is exactly what you have, 2 similar machines and it only happens on one. Do you have a thought on why? This is what makes it tough to solve, and possibly why Dell can't fix it? Need to recreate it I'm sure, do you know why it happens? What is the difference between the XPS's in terms of s/w installed and running? Device Drivers, etc.

Have you tried switching the Nvidia cards from one XPS to the other? Does the lock-up follow the card? Are the RAM cards identical? Have you switched those? Those 2 steps would help pin down the problem if the lock-ups follow the cards or memory.

Did you install the V2.3.0 BIOS in the failing XPS? Did it stop the lock-ups?

If you can figure out how to make it fail, I'm sure Dell would like to have your 2 PC's to look at them.

As for me, I've been told they are working on the problem. They wanted my XPS back. I couldn't do it as they did not want me to wipe it clean, had to be as-is... nope, too much personal and financial data on it, as well as single machine licensed programs. Swapped XPS had no guarantees it would be new. Configuration might be different too... but at least what I had.

Interesting that the one with all the extra components doesn't freeze...

You can also go to the Support site and enter the Service Tag for each PC, one at a time. Then over on the right side, click View Product Specs under Quick Links and compare the component lists.

There has to be something different about these two PCs to account for the performance differences.

@DataKill  Is the one that's "extended with some HBA DC614 to support 4 more SSDs" the one that freezes or not?

Since you have one that freezes and one that doesn't, it could be very helpful if you document the exact specs of both PCs, side by side here, including:

• motherboard version
• BIOS version
• BIOS settings for RAID vs AHCI, Secure Boot, TPM, etc
• amount of RAM, sizes and slots for each module, RAM manufacturer(s), rated speeds, latency, etc. You can use CPU-Z (free) for this info.
• SSD brands and sizes
• HDD brands and sizes
• monitors and video input ports used
• GPU output ports used
• keyboards
• mice
• etc

This may be extra work for you, but maybe this can help Dell and users see a component or setting that's common to their PC and possibly related to freezes...

@RoHe as requested
the following screens are from the nonfreezing machine (the good one).

Slot#1 to Slot#4 are populated with the shown module.
I removed the Kingston and replaced 2x8GB with 4x16GB.
All 4 modules are from the same batch. 

The added SATA-SSDs are 6x SanDisk Ultra 3D
4x 2TB on DC-614e
and 2x 4TB on mainboard on black/black

Can't post more as 10 Pictures - didn't know that restriction here.
Well, I'll see if i can get the 2 BOMs in one picture and then I'll post it here.

*sorry* don't know why the last 5 pictures also now crossed out, when 10 pictures per day are allowed.
In edit mode i can see the pictures. Don't know how this board works, but it seems to be a little bit buggy.
____
DK

Probably going to have to wait under the moderators approve the second set of pics. You will always see them, but no one else can see them until they're approved...

I looked at your data and compared it to mine.

Differences are I have an i7 non-K version, an RTX-2060, different boot SSD (WD), and less RAM that happens to be Single Channel vs. Dual that you have (I was thinking this was the cause for me, but you ruled that out, thank you ).

Yes, there were some voltaqe and speed differences, but I wouldn't expect them t matter, I could be wrong??

Thanks for the posting.

@DataKill  - Excellent!

I don't know if those Core VID voltage differences (1%) and Core Speed and Multiplier differences (4%) are within quality limits for the Core i9-11900K CPUs and for the PSUs. But the differences seem odd - to me- that the freezer is running at higher voltage and speed.

And then there's the difference between RAM Rank. Both PCs are running in Dual Channel Mode (Memory tab), but the freezer is using Single Rank RAM (SPD tab) while the good one is using Dual Rank RAM.

Channel Mode and Rank are entirely different, where Rank indicates how the chips are physically wired together on each module. 

It's a long shot, but it might be interesting to transplant all RAM modules between the two PCs so the freezer is now using the Crucial Dual Rank modules and the good one is using the Single Rank RAM Kingston modules.

If the freezing follows RAM Rank, you will have figured out a cause, which maybe Dell engineering can then use to find/fix the problems once and for all...

@ispalten - Awww, come on... "freezer" = @DataKill's PC that freezes. DOH!

Yes, you're running in Single Channel mode, while DataKill's PCs are both running Dual Channel mode, but you have Single Rank RAM, which is same RAM Rank as the freezer while the good one has Dual Rank RAM. So that's a clear difference.

@RoHe 

Ron, what are you calling 'freezer? I can't see that.

By the way, same data on my XPS (and I have a SINGLE 16GB RAM stick so I am truly Single Channel).

I've not seen any differences besides the amount of RAM, Nvidia card (PCI-E 3 vs. 4), and the CPU?

Anything catch your eye here to a major 'ahh hah'?

I don't believe that the SSD and the RAM are the root cause.

RAM - okay DELL is not using the best solution when selling modules with Single Rank compared against Dual Rank - attention do not think that Single Rank and Single Sided is the same and Dual Rank is also not the same as Double Sided. - there are some good explanations in the web.

I choose 2Rx8 over 1Rx16, because of its performance. I real life the 2Rx8 are faster then the 1Rx16 that DELL uses in their builds. But be careful I say not that in all configurations 2Rx8 is faster as 1Rx16, it depends on you memory controller and how many channels per chip could be addressed. Also there could be some compatibility issue when extending your amount of RAM when trying to use mixed modules. There are some good articles about this, so I don't go deeper in this.
When you have the original modules inside all should be fine either 1Rx16 or 2Rx8 build in.
I also did extended memory test using Memtest86+ - so there are no issues with the RAM on both machines. Also the DELL testcheck inside the Bios said all is fine with the memory.

Regarding the differences - clock/voltage/speed differences
Well when CPU is allowed to use all power/sleep modes and intel speedstep, and OS energy-savings you see that your cpu/ram clocks are tickling and changing the whole time, depending on the current workload. So nothing special, i also can make new pics with clock/timings that are total different from the shown for cpu. But I think that is useless.

What I have in mind, that the power/sleep-states from the cpu can cause the lock-ups, because the machine that lock-ups here, didn't lock-up when under heavy load, e.g. gaming.
But it lock-up when it is more to idle or soft workload, e.g. move mouse to come back from screensaver and *boom* lock-up.
Well we both only use the Mystify and the Ribbons screensaver, because you see that your machine is lock-up when there is no change on the screen anymore.

Keyboard/Mouse
I don't believe that these devices have something to do. But as requested we both have different keyboards - i use an very old "Microsoft Sidewinder X6 Gaming Keyboard" and the other one is "LogiTech Illuminated Keyboard", also a couple of years old.
We both use Alienware 510M Gaming Mouse.

Display-in/GPU-out
We have different displays
nonfreezing machine: 2x iiyama XUB2790HS-B1 connected through DVI - DVI/DP-adapter
lock-up machine: 2x DELL P2419H connected through DP - DP
I don't believe that the displays and used connectors have something to do with this issue.

Comparing the BOM of both devices.
Well I didn't find a good way to merge both in one picture.
So I downloaded the BOM as csv and try now to merge them readable in one excel-sheet,
at the weekend. *sorry* for missing this out for now.

@RoHe 
Anything else you need or want to know for this issue, from my both machines?

@RoHe 

regarding Single Rank vs Dual Rank - it also was in my mind, but as far as I know DELL uses in most builds of this XPS generation 1Rx16 from multiple brands.

I could be more specific because I bought over time more as 10 XPS8940 mostly i7-11700 with 16GB over ebay and refurbish them, because all are ripped off the graphics card, so i bought them very cheap. All come with origin RAM modules.
As far as I know, the RAM modules are 1Rx16 when config was 2x8GB, 
if you ordered one with 32GB you got  2Rx8 when config was 2x16GB.
and as far as I know DELL never shipped XPS8940 configs with 4x8GB on their own.
There is also a sheet with supported module-configs, it is surprising, but not all possible configs are supported by these XPS machines.

So if there is a specific issue, within the amount of Ranks, Dell should know because they should be able to track down this issue by themself, if they tested properly. But who knows? Maybe there are more XPS owners outside with issue running only single rank modules? But interessting if there are also owners with origin dual rank modules facing lock-ups.

Well, sidefact, I worked in the past for a memory company (in their it/tech division), so I can say I know how vendors should testdrive their builds and how to check compatibility.
____
DK

@DataKill  I think you covered things quite well, thank you!

I'm not convinced that RAM rank isn't an issue here. Your freezer has single rank RAM as does @ispalten's PC which also freezes, while your good one has dual rank RAM.

There could be an issue with the RAM controller that doesn't deal very well with single rank RAM after PC has been idle for a while.

The way to test that would be to swap RAM between the 2 PCs. I understand fully why you wouldn't want to do that. It's entirely your decision and I accept that. But, now that I know about this difference, I'll pass the info over to my Dell tech contacts and let them see if that helps them figure this out....

---

@DataKill wrote:

RAM - okay DELL is not using the best solution when selling modules with Single Rank compared against Dual Rank - attention do not think that Single Rank and Single Sided is the same and Dual Rank is also not the same as Double Sided. - there are some good explanations in the web.

I choose 2Rx8 over 1Rx16, because of its performance. I real life the 2Rx8 are faster then the 1Rx16 that DELL uses in their builds. But be careful I say not that in all configurations 2Rx8 is faster as 1Rx16, it depends on you memory controller and how many channels per chip could be addressed. Also there could be some compatibility issue when extending your amount of RAM when trying to use mixed modules. There are some good articles about this, so I don't go deeper in this.
When you have the original modules inside all should be fine either 1Rx16 or 2Rx8 build in.
I also did extended memory test using Memtest86+ - so there are no issues with the RAM on both machines. Also the DELL testcheck inside the Bios said all is fine with the memory.

---

If you look here, https://www.oempcworld.com/support/singlevsdualram.html, you can see the RANK definition. Not related to Dual and Single Channel...

With only a 16GB stick, I am single channel... more on that here, https://www.hardwaretimes.com/single-channel-vs-dual-channel-ram-which-one-is-better-for-gaming/, and I am thinking that might have been my problem...

Performance though is not probably noticeable for me. I've did order 16GB from Crucial, and 'hope' it will work with the one stick from Dell that I have?

@RoHe, ahh, 'Freezer' is the PC that freezes... Got it now, some days I'm slow

My thought on all this though are quite different...

Basically I'm thinking of 'why' does the BIOS version make a difference?

Having worked on some BIOS it is not a complicated process... Does the POST, loads a BOOTSTRAP to locate the OS loader, initializes some h/w and starts drivers for devices... and I guess, can do other things.

Could it be loading the wrong driver? Doubt it...

So the next thing I feel it might be is TIMING...

A 'freeze' is happening somewhere, either some code got an unanticipated return code and just stopped. Meanwhile the OS is waiting for it to return control to them and it isn't getting any?

Could be a timing issue I guess too, hard to tell as there are no errors anywhere.

It does have to be in the OS as the CLOCK stops...

What I can't figure out is how this relates to the BIOS version? Nor why some 8940's with Nvidia cards freeze and others do not? Not to mention the 2 users of Linux with Nvidia cards that have freezes... sort of eliminates Windows as a cause I think, no?

So the COMMON culprit IS H/W and BIOS, which I guess is more F/W than S/W?

Comments?