XPS 8940, randomly freezing

I already posted my CPU-Z captures @ 07-28-2022 08:50 AM in this thread. Look at those.

Yes, I am running @ 2933Mhz speed. You can see that too in CPU-Z, since it is DDR4 RAM, you multiply the CPU-Z speed by 2. Same value than that I see in Task Manager:

By the way, if you get AIDA64 (not free but there is a free trial) it does show the correct SLOTS that the DIMM's are in, naming them DIMM 1 through 4. Yes, WMIC shows it wrong too, I posted those in another tread here too.

It is probably due to how the programs read the DIMM location I guess? However, AIDA64 proves it is possible to get the slots right.

Still, this is off the subject here, RAM and how configured doesn't seem to be the trigger or cause of the lock-ups.

I am aware that performance difference are minimal at best. I am thinking if the memory controller has to work with 2 DIMM's on one channel it 'might' be faster than one DIMM each on each channel?  Assuming that is correct, however, it is possible one being Dual Rank could offset or do better in that configuration. In any event, one would probably never notice that, expect possible in some Performance testing programs?

If I want to be SURE, I'd replace the Single Rank DIMM and have both Dual Rank DIMMs on the first channel.

There are links on the web that sort of say that:

https://diamondlobby.com/tech-guides/how-to-enable-dual-channel-ram/ 

That one could be right, I'm not sure? Problem is is CPU-Z correct? That is are you really running Dual Channel AND Dual Rank on 1 channel? 

Another, https://www.techradar.com/how-to/how-to-install-ram  and it doesn't even consider Dual or Single Rank?

Want some more confusion, https://www.compuram.de/blog/en/single-dual-and-multi-channel-memory-modes/ and it confuses RANK with how many sides chips are on.

I am not sure there is a real difference no matter how you install them. I also don't trust CPU-Z's data for slots. I am also not sure about mixing Single and Dual Banks/Channels offers an plus over both Ranks on one bank running Single as the Memory Controller doesn't need to switch banks and saves some time that way? 

Doesn't matter I guess, both work, and has no bearing on this problem here.

Okay, found your cpu-z screenshots.  Was having trouble earlier due to Dell's formatting problem (which am glad they got fixed) trying to find or see things.  It's interesting then that you have your RAM in slots 2 and 4, which according to my info should mean you are only using Channel# 2, color coded black.  But cpu-Z obviously says you are in two channel mode: 2 x 64-bit.   I think I just assumed I needed to have one stick in Channel# 1 (white coded) and one stick in Channel# 2 (black) to get dual channel running at 2933MHz, which is obviously not true.  I came to this conclusion from reading https://www.dell.com/community/XPS-Desktops/XPS-8940-SE-third-party-RAM-cannot-run-at-2933MHz/td-p/7729441/page/3

Where the author states "don't have the same brand of memory in either channel," and so set mine up accordingly.

Regarding RAM rank, which indeed adds more confusion at least for me, I have not encountered that variable until now.  I do see that your micron stick's Rank says single whereas mine says dual, but have no idea if that means anything related to freezing or performance.

I agree that it does not appear one's memory configuration, as long as it works, on the xps 8940 has anything to do with this freezing/locking issue.  Sorry about that, since our configurations appear to be very close. 

You are correct and my notes are not.  From the CPU: Slots 1 & 3 are Black, Slots 2 & 4 are White.  Is the memory the only thing you added or replaced on your xps 8940?    Did your pc freeze before adding the memory?

Maybe your 8940 slot colors are different from mine, but from the CPU they alternate black and white slots. That is Black is slots 1 and 3,  White is 2 and 4. White slot 2 from the CPU is where Dell installs the first DIMM when you have a single DIMM as I had. That is the White Clips first.

See https://www.cgdirector.com/ram-slots-use/ as well.

I don't think the Channel # is that important as is the spacing from the CPU for heat and air flow.

Here is the Motherboard picture:

DIMM 1 and 2 are in Channel 1/Bank 0, and have the White Clips as you can see. These 2 White slots it appears is what CPU-Z calls Slot1 and 2?

Well, I only had 1 16GB DIMM as delivered by Dell in the 2nd Slot, first White one from the CPU. The 'standard' configuration was 2 8GB's of RAM, but 1 16GB was a free option and I knew I wanted to get more RAM later.

I never locked-up (the term 'freeze' to me mean a temporary 'stall' and then it continues, like a 'stutter') until last Jan. when BIOS V2.4.0. was released.

Recently, I bought a 16GB DIMM from Crucial and added it as the 2nd DIMM on Channel 1/Bank 0,

I am on BIOS V2.8.0, and continue to Lock-up, about every 2 weeks ore less.

Since the first chip is the Samsung Single Rank, both DIMMs run as Single.

That's odd then that you had the temporary freezing issue with no H/W changes, which would seem to point to the BIOS update.  However, after that you adding the Crucial stick in slot# 4, but the updated BIOS did not completely fix the problem.  On that "freezes completely" discussion Rohe states,  "There has been an indication these XPS 8940 freezes might be related to RAM rank. Dell installs either single or dual rank 16 GB OEM modules in the XPS 8940. A user removed the single rank OEM RAM and replaced it with dual rank Crucial RAM and the problems disappeared."    In your case, CPU-Z shows the Crucial as single whereas mine shows dual.  I am using Crucial model# CT16G4DFD832A in slot# 3.  If there is no difference in the model#, you might try seating the Crucial in slot# 3.  Also, does the freezing occur whether you're on the network or not?

@ishmael 

No, I had a LOCK-UP, never a temporary freeze. Only way out, use the Power button to turn off the XPS and then on again to be able to use the PC.

Slots 2 and 4 are Channel 1 so I wanted to add that to have 32GB's in one channel rather than 16GB's in 2 channels. Less work for the Memory Controller.

No, there is no indication of RAM rank that can be proved.. only one user here has 2 XPS, one all Dual Rank, the other all Single Rank DIMM's. That I think is what has RoHe thinking that Rank is the problem.

We've also had users with only Single Rank that do not have the problem.

So right now, the only 'proof' that seems to exist is if one goes back to BIOS V2.3.0 the problem goes away, but again, not for everyone.

My DIMM is an CT16G4DFDA32A and I think I've got something that might be a Single Rank one. On Amazon it is spec'ed as "Rank and Configuration = 1Rx8 or 2Rx8 ", but isn't showing as Dual. It could be because it IS operating correctly as a 1Rx8 when it is in the SAME channel as a Single Rank DIMM.

Some people have had problems mixing Ranks and/or DIMM GB's. I have had no problem.

I'm waiting for Crucial to answer me on what happens when I mix it with a Single Rank DIMM. I suspect it is capable of working with either function of the Memory Controller.

Hey all,

just spamming the various similar threads with a solution which seems to be working for me(so far), sorry if unrelated:

https://www.dell.com/community/XPS-Desktops/XPS-8940-Intermittent-Freeze-Possible-Solution/m-p/8246339#M74004

Voi siete corretti, mentre le mie note non lo sono. Dalla CPU: Gli slot 1 e 3 sono neri, gli slot 2 e 4 sono bianchi. La memoria è l'unica cosa che avete aggiunto o sostituito sul vostro xps 8940? Il pc si è bloccato prima di aggiungere la memoria?

@meharg 

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

You are correct, while my notes are not. From the CPU: Slots 1 and 3 are black, slots 2 and 4 are white. Is memory the only thing you have added or replaced on your xps 8940? Did your pc crash before adding memory?

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

I assume you were replying to me.

Only added an External USB drive, and yes, locked up once BIOS V2.4.0 came out in Jan.2022 and all BIOS versions after that, both with the Dell shipped RAM and added RAM later.

Hi Irv,

Did you get your lockup issue resolved? 

---

@ishmael wrote:

Hi Irv,

Did you get your lockup issue resolved? 

 

---

Sad to say, I did NOT!!!!

First, since I could not get a clear answer from Crucial (actually Micron it seems) on the 1Rx8/2Rx8 issue on the CT16G4DFDA32A, as it was running a Single Rank, I returned it and bought 2 16GB CT16G4DFD832A's that another user here had and was running Dual Rank. The reason for thinking maybe Dual Rank was the reason NOT to have the lock-up was a post by @DataKill here who had 2 'identical' XPS's. One had  4x8GB Single Rank Dimm's and the other 4x16GB Dual Rank Dimm's. Only the Single Rank XPS locked up.

With the 32GB's Dual tank in my XPS's White Clips, I was running Dual Rank, Dual Channel.

I had the Mixed Samsung and single Crucial I returned on V2.8.0 for about a week and made the switch. For 4 more days I recall (didn't keep notes but knew when I got the new sticks and put then in) and no lock up. Well, that might mean it was fixed in the V2.8.0 BIOS even, so I went and installed V2.4.0 again.

Sad to say, on Day 5 running V2.4.0 I left the house around 8AM, came back around 10AM, and the Desktop was still showing on the monitor, lower right hand Systray clock read 8:12AM...

Took longer to fail, but it still fails. It appears RANK of the Dimm is not the answer, or at least not the full answer.

The only other question though would be the Intel Management Engine. See, when you roll back the BIOS versions, they do include the Management Engine version for that date the BIOS was built. However, Intel doesn't allow the s/w to be back-leveled. So I was running BIOS V 2.8.0's ME V14.1.65.1990 with BIOS V2.4.0's included ME V 14.1.60.1892. Before on V2.4.0 I could not even stay running 2or 3 days, but this time 5? BIOS V2.3.0 had an ME V14.1.53.1649 by the way, which never would back-level either, but going from V2.4.0 to V2.3.0 did solve the lock up problem?

So I am wondering if there is any involvement with the Intel Management Engine and the lock ups? Hard to say? Both the BIOS and ME have CVE's included. Those may not be made public until they are fixed, and some are Fixed 'quietly' before announce (as in the description in fixes include as 'and other fixes' that are unnamed). One never knows? Possible the V2.8.0 (V2.9.0 appears to include the same ME) works better and that explains the longer time between locking up on V2.4.0?

I am on V2.9.0 right now. 2 days only... I don't have any expectation that I will not lock-up again. I feel until Dell opens up and posts here what it knows, and when it expects to have the BIOS/Nvidia problem fixed we'll never know? Either that or 'we' users start collecting information and send it to a Dell Moderator to present to Level 3 Support.

There are people with Nvidia cards on 8940's that DO NOT have the problem. Even on the XPS8950 users with the same Nvidia cards are not seeing the problem? Why is the real question?

Need to see what people have, both those that do and do not have the problem. Data like:

• BIOS Version
• Nvidia Card
• Nvidia Card RAM
• Monitor Resolution
• Monitor Port used
• Intel CPU
• XPS Standard or S.E model
• XPS RAM total
• XPS DIMM size in GB's
• XPS DIMM slots used
• DIMM Rank
• Windows Version
• Any BIOS changes other than turning off Capsule Update
• Is SSD running RAID or AHCI
• Any ADDED internal h/w (disks, PCIe cards, etc)
• Any ADDED external devices (USB Hard drives, non-Dell wireless Keyboard/mouse, etc.)

Just maybe with enough of the above data one could find the common element that one could have that causes the fail?

So confusing, and so frustrating. Any time one has a lock up, data could be lost. I've had 2 programs get mangled Settings already. I feel the only sure fire fix right now IS an AMD video card!!!

By the way, it isn't only Windows users, at least ONE Linux user has the same problem, and is not even Stable (does not lock up) under BIOS V2.3.0! What does that tell you?

It has been almost 7 months now with no relief... Dell really needs to get this fixed fast!

@DELL-Chris M , what is the status of this problem!!!

Oh, you populated both channels:

"Memory: 16GB single rank stick (SK Hynix) in slot# 2, added a second 16GB dual rank stick (Crucial) in slot# 3."

You might as well use Slot 2 and 4. Might show a slight speed improvement. As it stands now the Memory Controller will have to switch channels. Putting them both on one (1 and 3 or 2 and 4) it would not have too. I''d be interested if you move the Crucial to slot 4 as well. Would stay Dual or switch to Single Rank? Really wouldn't matter, I don't think the Memory Controller switches, it stays at the 'speed' and 'settings' of the slowest DIMM.

You could tell by running some performance tests that test Memory Speed in each configuration.

Mine are 2 of the same Crucial DIMM you have but in one Channel, not one DIMM in each.

Passmark had Performance Test 10.2 (free 30 day trial) that you can run. My results:

If you ran it, it might be slower I'm thinking? Interesting to see the results and if you were to put the 2 DIMMs in one channel as well.

Steve,

I thought I knew 2 people had Dual Rank, but the one I knew for sure had no problems... his other XPS with only Single Rank had the problem.

What annoys me is the loss of settings on some programs. Pain, especially like my Backup program didn't show it until I looked in the settings. I get email what it completes, and I usually don't look at the content, but I did and discovered it took only about an hour vs. the normal 3+, It was using the default incremental method for backup, not the Full I normally used.

All I can grasp at is what has changed or a difference from me to others but not many post they didn't have the problem. So I look for common stuff to rule things out.

Dell may or may not be working on this? They sure are not telling up. Dell may not own the BIOS code either, usually provided by the Motherboard maker, and that would probably be a 3rd party. Also the Intel Management Engine is included in the BIOS and that might come as a binary from Intel.

In BIOS 2.3 to 2.4, and almost all the ones later, the Intel Management Engine is updated, but you can't go back it seems?

Here is what the one is when I tried to put V2.3.0 over 2.9.0:

This is what V2.4 contained:

So, as you can see, not only was BIOS code itself changed, so was the Intel M.E.

As you try to go back, the Intel M.E. fails to install and you are left with the latest one you had installed.

Of course, going back to V2.3.0 over 2.4.0 seems quite stable but you were still using the V2.4.0 Intel M.E.?

Both Dell's BIOS and Intel M.E. have CVE's contained as part of the fixes and probably some that are not publicized immediately either. Covered with 'and other fixes' by Dell.

Surprising to me that the 8950 users with the same Nvidia cards have not hit this problem? Dell has not made much progress in 7 months either...

I feel the only way out is to dump the Nvidia card? EXPENSIVE proposition too.... Even an AMD similar cards can be over $300 or more.

I wish Dell could/would fix this or do a FREE swap out for ATI cards of the same RAM size.