XPS 8940 memory upgrade: Crucial disaster, Dell memory modules 100%

Question

Ten days ago, a new XPS 8940 I'd bought arrived - i7, 16Gb RAM, 500Gb SSD, 1Tb HDD, GeForce 3060 Ti. A popular configuration judging from seeing similar configs mentioned here. This new machine will replace the XPS 8930 i5 system I bought in 2018. It's done well!

I decided to upgrade the memory to 32Gb. I do quite a bit of video work including live and recorded presentations plus experimenting with virtual environments. I figured 32Gb total, in combination with the rest of the system, would be fine for what I need from a desktop computer for the next few years.

So I bought 2x8Gb modules from Crucial to extend the total RAM capacity from the installed 2x8Gb modules. I felt reasonably confident with Crucial's analysis of the system and recommendation on which Dell-compatible modules to purchase which I did through Amazon UK as Crucial were out of stock - https://www.amazon.co.uk/gp/product/B08C53LL9J/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&th=1.

The outcome was a disaster! The new additional memory caused myriad BSODs and error messages about corrupted system files on booting and being unable to load Windows. Example screenshot here.

It even triggered SupportAssist to submit an automated critical-event report and the support agent I spoke to on the phone late on Jan 28 my time even spoke of replacing the machine with a new one.

But once I removed the Crucial modules from the computer, everything was back to normal. No BSODS, no errors, no failed bootups. A comprehensive in-depth pre-boot diagnostic that lasted some 4 hours passed all the tests and showed no errors at all.

My feeling is that, rather than blame Crucial, it's more than likely that I bought the incorrect memory type through not fully ensuring that I'd chosen modules that were 100% compatible with the 8940. That act was the catalyst for the catastrophic errors that subsequently happened. Luckily cost-wise, Amazon refunded me with no questions asked as is their standard.

I still wanted the extra 16Gb RAM. This time, I went with Dell's memory upgrade, specifically this one - https://www.dell.com/en-uk/work/shop/dell-memory-upgrade-8gb-1rx16-ddr4-udimm-3200mhz/apd/ab371021/memory?ref=frommyaccount

The key decider was that the product description includes this phrase: "it will work with your specific Dell System so it is fully compatible and supported by Dell." And the list of compatible systems specifically mentions the XPS 8940. I'd also read @DELL-Chris M memory explainer for the 8940 (which I hadn't read before) - https://www.dell.com/community/XPS-Desktops/What-are-the-Dell-memory-specifications-per-slot/m-p/6053874

The order arrived a few days ago and I installed the modules. Seamless and painless, no errors of any type, the computer just works as you'd expect. Screenshot of all modules in place.

Learning experiences:

If buying from Crucial or any third-party supplier, first do thorough research on specifications to be as sure as you can that you buy compatible memory.
Read Dell's documentation including community posts to see what others' experiences are.
If something does go wrong as in my experience, report it immediately to Dell tech support. You'll be on record for prompt action that may help if it turns out you do need warranty support. Plus you'll have access to knowledge and insights that may be helpful.

fireberd · Answer

Crucial is the primary brand we recommend for non-Dell memory as Crucial guarantees their memory to work in a Dell (using the correct models). However, mixing memory, on any PC not just a Dell, can be a disaster. We always recommend only using one brand/type memory.

An example. I had a self built desktop using an ASUS (gamer) motherboard. I had 16 GB of Corsair memory and 16 GB of GSkill memory, both same type. Either worked perfectly, but if both brands were installed I would get a memory error and it would not boot.

Luke717 · Answer

Yes, I'm sure I've seen comments in this forum that Crucial is the primary brand Dell recommends. I'm pretty sure my bad experience with Crucial is down to my error in not ensuring I was buying 100% compatible memory.

As for mixing memory, you're right, it can be a disaster as my experience clearly indicates if you get the mix wrong. Like you, I had a self-built system a decade ago. It had different memory modules from different brands, but all worked together just fine.

Still, I'd agree that a rule of thumb is - best not to mix different brands in the same system.

Mary G · Answer

See the ram configurations in the manual XPS 8940 Setup and Specifications | Dell US 4-8gb is not supported.

Luke717 · Answer

@Mary G my 8940 arrived from the factory with 16Gb of RAM comprising 2 x 8Gb modules. I've added two further Dell modules of 8Gb each to make a total of 32Gb RAM.

The memory configs for 32Gb shown in the manual you mentioned don't say that this config is supported. I suppose it means that if I want a 32Gb memory configuration, I need to buy and install modules in one of the options mentioned:

32 GB, 1 x 32 GB, DDR4, 2666 MHz/2933 MHz, UDIMM
32 GB, 2 x 16 GB, DDR4, 2666 MHz/2933 MHz, UDIMM, dual-channel

So not 32 GB, 4 x 8 GB, DDR4, 2666 MHz/2933 MHz, UDIMM, dual-channel which is what I have.

The BIOS reports the total RAM of my new 32Gb configuration and states details about it including speed, channel mode, and size of each DIMM:

I used CPU-Z to look at the details for each module in each slot: it reports exactly the same characteristics for each module except the manufacturer info which is split between SK Hynix (who made the two modules that came in the 8940 from the factory) and Samsung (who made the two that I subsequently purchased from Dell:

I guess I'm concluding that even though my new memory config isn't made up in the configuration the Dell manual states, it all works without any errors at all. None of the Dell diagnostic tools I've used flag up anything about an unsupported configuration.

I'm inclined to leave things as they are. I don't see a downside in this, unless I'm missing an important point?

RoHe · Answer

Maybe I missed it, but did the new Crucial pair work properly when you removed the OEM pair and put the new ones in the 2nd and 4th slots, counting from the CPU (with matching color retention clips)?

If they had problems, that suggests these modules (a) aren't compatible, (b) one/both is defective, (c) one/both is fake Crucial RAM. (Fakes are not uncommon online, even at those "big" sites.)

The XPS 8940 also has a strange memory slot quirk. So assuming you haven't sent the Crucial pair back and they work properly when they're the only modules installed and in slots 2 and 4, try this...

Power off, unplug and press/hold power button on PC for ~15 sec
Open case and remove motherboard battery
Press/hold power button for ~30 sec
Install the original Dell OEM RAM in the first 2 slots counting from the CPU. These slots have mismatched retention clip colors. And yes, I know that's not the "normal/right" way to install RAM, except for that quirk...
Now install the Crucial pair in remaining 2 slots, which also have mismatched retention clips.
Reinstall the motherboard battery, close up and test system now...

Luke717 · Answer

@RoHe thanks for the suggestion. I already returned the Crucial modules to Amazon and already received the refund (they're quick like that

I think the Crucial modules were not compatible. When I installed them I could not do anything like inspect their characteristics in CPU-Z as the computer gave out the critical errors right from boot. It didn't even get to loading Windows.

Here's a pic of one of the many 'Recovery' error screens I got when starting the PC:

Every similar screen mentioned a different system driver but all with the same Windows error code 0xc0000221. A search on Microsoft's websites pulled up many references including one with this succinct comment:

0xc0000221 is often a hardware issue - either hard drive or RAM (especially if you have recently added any new RAM).

Running the pre-boot system diagnostic got many errors too including this one:

This Dell page shows that error code 2000-0114 is to do with the CPU https://www.dell.com/support/kbdoc/en-uk/000181167/reference-table-of-epsa-psa-error-codes-and-troubleshooting-steps-2000-0nnn-series

It suggests updating the BIOS to the latest version. One of the first things I did when I got the machine, before this memory situation, was to update the BIOS to the latest version 2.4.0 and update other Dell drivers as required.

Once I removed the Crucial memory when all these errors happened, the computer performed wholly as expected with no errors of any type.

My only concern right now with the new Dell modules is from the info @Mary G shared where the memory config stated by Dell does not specifically speak of 4x8Gb modules. So what would be the consequence on warranty if, say, a problem arose where the memory is part of it. Would that invalidate the warranty? I'll reach out to Dell to ask!

fireberd · Answer

If its all working properly with the four 8GB modules I wouldn't be concerned.  We have seen, on occasion, wrong or incomplete information in a Dell manual.

RoHe · Answer

@Luke717 The configs listed in the specs are only the ones Dell validated on this particular PC model. It doesn't mean that unlisted configs won't work, only that Dell never tested them.

Lots of examples of RAM configs on various systems that Dell didn't list in those specs but still work properly.

I wonder if somebody just sent you the wrong modules and/or you fell victim to that RAM slot quirk which others have seen, and resolved simply by mixing pairs in each bank (slots same color retention clips).

Tesla1856 · Answer

Don't mix DIMMs. (period)

Sometimes, why DIMMs don't work (but are seemingly spec-ed properly otherwise ) and you are not mixing (or just trying one) ... is the Ranking (or how the memory chips are physically laid-out).

Along with the other specs, this ends-up making most Dells and Alienwares fairly finicky about memory. This is not the old-days. The memory is being-run very fast and there is little tolerance.

Better to just get all the memory you need at time of system purchase.

Luke717 · Answer

@fireberd wrote:

If its all working properly with the four 8GB modules I wouldn't be concerned. We have seen, on occasion, wrong or incomplete information in a Dell manual.

Thanks for the reassurance!

Luke717 · Answer

@RoHe wrote:

@Luke717 The configs listed in the specs are only the ones Dell validated on this particular PC model. It doesn't mean that unlisted configs won't work, only that Dell never tested them.

Lots of examples of RAM configs on various systems that Dell didn't list in those specs but still work properly.

I wonder if somebody just sent you the wrong modules and/or you fell victim to that RAM slot quirk which others have seen, and resolved simply by mixing pairs in each bank (slots same color retention clips).

Got it re unlisted configs, thanks.

Re the wrong modules being sent, you're referring to the Crucial memory I bought from Amazon, right? I guess that is possible. This thought just adds more to my resons why I wouldn't buy RAM modules that way again.

Luke717 · Answer

@Tesla1856 wrote: Don't mix DIMMs. (period) With you on that!

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XPS 8940 memory upgrade: Crucial disaster, Dell memory modules 100%

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