Just a thought here. Have you tried to pull the CMOS battery, leave it out for 15 minutes, then reinstall the battery and reboot? I had a Latitude that would not boot with a proper RAM expansion and that worked on my system. The Crucial RAM especially should work. Also does one RAM module from the Crucial kit work at all?

Unfortunately, the CMOS reset also didn’t work. Have to say that this is the first Optiplex that I have seen this happen. This looks like a new feature where Dell is essentially forcing me to buy their Ram (5 times market price).

Definitely not a good experience, spent hours on their helpline as well, but no solution was offered other than “we only offer support for Dell parts”. I have tried other brands also like Kingston and Corsair.

Not unethical. Dell has always used OEM (original equipment manufacturer) customized hardware (PSU, CPU, video cards, memory, etc.) purchased from the manufacturer to meet our conservative restrictions (VBIOS, System BIOS, drivers, etc.) based on our chosen thermals.

We can only support the 8GB OEM memory stick that we actually tested and validated in that model.

29NJ4 8GB, DDR5, 4800MHz, 1RX16, 1Gx64, Unbuffered, 288 pin, Single Rank, Non-ECC, Non-Encrypted, Samsung M323R1GB4BB0-CQK

Dell oem ram is $44 on amazon.  It is identical to the one Dell shipped in PC.

Samsung M323R1GB4BB0-CQK 8GB DDR5-4800 PC5-38400 4800MHz UDIMM Non-ECC UNBUFFERED Desktop RAM Memory Module

https://www.amazon.com/Samsung-M323R1GB4BB0-CQK-DDR5-4800-PC5-38400-UNBUFFERED/dp/B09RWH76M5

DP/N 29NJ4 is the same oem ram Dell had used in Optiplex 7000, XPS 8950, Aurora R13.

29NJ48GB, DDR5, 4800MHz, 1Rx16, 1Gx64, Unbuffered, 288 pin, Single Rank, Non-ECC, will operate at 4400MHz
Hynix HMCG66MEBUA, Micron MTC4C10163S1UC48BA1, Samsung M323R1GB4BB0-CQK

regarding Dell ram price, buying from Dell is almost always at premium price targeting the enterprise community, but average user does not have to buy from Dell.  Using the memory maker model number listed by Dell mod will often find third party deal price.

Re:  PC came with a Samsung 8GB RAM (DDR5 UDIMM 4800MHZ). Samsung M323R1GB4BB0-CQK.  Crucial DDR5 CT2K16G48C40U5. Exact same specs as the shipped version

The Crucial memory spec is not exactly the same as the validated oem ram by Hynix, Micron, Samsung. 

Ok, so a generic no name RAM that you found on Amazon is better than Crucial (owned by Micron) or Kingston? And again, I am well aware of RAM specs in detail. I am an electrical engineer. Care to elaborate on what exactly is the mismatch between the Crucial RAM and the system requirements?

This was a corporate purchase, so not sure what you mean by regular user and premium user. The 32 Gb Ram in Singapore is available from Dell for $670. Check Dell website. I bought mine from Crucial for $150. The original PC with 8Gb RaM was $1370. See what I mean by captive upgrades?

@redxps630 not sure if you are trying to help users? Or just towing the Dell line?

When you say “support”, you mean offer technincal help for installation? Yes, I get it and agree. You should only offer help for RAM that you have validated and tested. But of you imply that your system will not accept anything other than your chosen brands, that is unethical. When purchasing the system, nowhere was it mentioned that RAM upgrades are restricted by brand. That is a limitation imposed by Dell, not for quality control, but purely to create a captive market for RAM upgrades. Using third party RAM voids the warranty anyway, so why would Dell care if I ruin performance of my purchased PC? As the Pc owner, I have every right to choose whatever brand of RAM I want.

also lets not pretend that Dell has some high mark standard for RAM or for that matter any component. Memory specs are fairly standardized and lots of large global reputed firms manafacture RAM based on industry standards.

Dell Optiplex is more expensive (marked up) possibly because it is "business class" orientated for corporate credit card expense.  It is not suitable for noncorporate user.

You have found out that Dell pc bios are unpleasantly finicky of what ram can work.  This is a well known fact in Dell desktop community.  It is more restrictive although user do not have to buy oem ram directly from Dell at marked up price.  Dell oem ram are usually made by Hynix, Micron, Samsung, Kingston. afaik all those memory brand names are more or less similar.  

spec of crucial model number CT2K16G48C40U5

DDR5 Density 32GB Kit (2x16GB) UDIMM Unbuffered Voltage 1.1V Speed DDR5-4800 CAS latency 40 Extended timings 40-39-39

spec of Dell oem Micron ram MTC4C10163S1UC48BA1

Crucial 16GB DDR5-4800 validated by user in XPS 8950/Aurora R13.

It appears these Crucial ram are identical: Crucial CT16G48C40U5 and CT2K16G48C40U5.  one is 1x16 the other is 2x16.

PS Dell Chris, it seem OP wants to upgrade to 2x16 GB.  can you please provide the Dell oem memory model number of 16GB ram?

Try to make smarter decision by reading up information, doing a little research on the product before purchase, especially if it costs large sum of money.

If you are lack of technical knowledge, can't build your own machine, visit a computer stores in your area and sale persons can help you to choose one that fit your usages.  If you are tech savvy and understand the computer stuffs, making sure to get the right configuration for your needs. I see that most computer companies do provide a configuration tool for their customers to select components for their customized machine.  That is a better way to shop comparing to a fixed built machine in store.

I don't know what an engineering degree and all that comparing on RAM sellers have anything to do with the way Dell made their products.  But the more you are boasting, the harder you will get laughed at.  Because you couldn't perform a simple task such as a RAM upgrade with that degree.

I'm just an average PC user and am still got a lot to learn.  But there are few things I disagree with your engineering knowledge.  Crucial sells memory made by Micron and Dell machines do use RAM from Micron and other brands, restricted by brands are farfetched.  Samsung memory is not generic brand. 

If something you couldn't make it work, it doesn't mean that others are with the same incompetency.  Maybe taking the tinfoil hat off and you can find the right RAM for your machine.  

When you are posting in a public community, expecting others to voice their opinions as well, dial back your attitude a bit, you may receive a working suggestion.  Beside the Mods (work for Dell), everyone here are PC users and contributors (like the other poster) who discussing issues, sharing their knowledge and providing working solutions to the community.  

Ok, so you typed out an entire essay, but didn’t talk about what specs on the Crucial RAM that I purchased are not compatible with my PC? And its not just Crucial, I have tried other brands as well.

The other user talked about Dell BIOS being finicky with non Dell or non verified RAM. I am telling you that with SFF 7080 Plus it is a bigger problem than before. I always buy Dell Optiplex and upgrade RAM.

@Chino de Oro people laugh at each other on these forums? Lol, that’s good. I actually have 2 degrees. But funnily, I don’t use them at all. 

@redxps630 thank you for the second response. I see you are genuinely trying to help. I have already tried those alternatives. The Dell BIOS does not accept them. Even tried CMOS reset.

Have the same issue, purchased Crucial  CT2K21G48C40U5 x 2, does not boot.

I would not have bought the PC if i could not upgrade it.

I also updated the bios today... still no luck