Teardown of Apple's iMac Pro shows RAM upgrades possible - with extreme difficulty
One of the first teardowns of Apple's iMac Pro shows that it is in fact possible to upgrade the RAM on the computer, though all but the most experienced people will probably want to pay a specialist.

The iMac Pro uses four quad-channel modules, in 8-, 16-, or 32-gigabyte assortments depending on whether buyers pick a 32-, 64-, or 128-gigabyte machine, a video by upgrade firm OWC reveals. While it's possible to boost RAM by swapping in new modules, as on a Windows PC, doing so requires disassembling virtually the entire computer, including a risky process to remove the display.
In its default $4,999 configuration with 1 terabyte of storage, the Pro actually uses two compact 512-gigabyte SSDs joined together in a RAID configuration, something presumably needed because of the minimal space available. These can be unscrewed and removed, though finding replacements is unlikely, at least for now.
OWC said that it will be selling RAM installations and even a do-it-yourself kit in the near future, but that given memory and labor costs -- and the trade-in value of the 32-gigabyte option -- it's best for most people to buy a Pro with sufficient RAM from the start.
The company's teardown also offers a glimpse at the Pro's elaborate cooling systems, needed to cope with workstation-level hardware being compressed into the body of an iMac.

The first iMac Pro shipments began arriving earlier this week. Check out AppleInsider's unboxing video, as well as our benchmark tests.

The iMac Pro uses four quad-channel modules, in 8-, 16-, or 32-gigabyte assortments depending on whether buyers pick a 32-, 64-, or 128-gigabyte machine, a video by upgrade firm OWC reveals. While it's possible to boost RAM by swapping in new modules, as on a Windows PC, doing so requires disassembling virtually the entire computer, including a risky process to remove the display.
In its default $4,999 configuration with 1 terabyte of storage, the Pro actually uses two compact 512-gigabyte SSDs joined together in a RAID configuration, something presumably needed because of the minimal space available. These can be unscrewed and removed, though finding replacements is unlikely, at least for now.
OWC said that it will be selling RAM installations and even a do-it-yourself kit in the near future, but that given memory and labor costs -- and the trade-in value of the 32-gigabyte option -- it's best for most people to buy a Pro with sufficient RAM from the start.
The company's teardown also offers a glimpse at the Pro's elaborate cooling systems, needed to cope with workstation-level hardware being compressed into the body of an iMac.

The first iMac Pro shipments began arriving earlier this week. Check out AppleInsider's unboxing video, as well as our benchmark tests.
Comments
These are machines for people who make their living from them. They’re not for hobbyists.
As long as I can afford their products, whatever their reasons are for locking up devices, I'll just pay for AppleCare as insurance. It's my choice. I like Apple products and for the most part they've never let me down. Although I've worked in IT, upgrading and servicing Windows desktop computer hardware, as a senior citizen I no longer have the eyesight or patience to be fiddling around with my home computers. As long as they stay working as well as when I bought them, I have no grievances.
Interesting OWC said RAM upgrades would/might be coming but didn't say anything about SSD upgrades(?). When I look at where all the desired replaceable components are, it appears Apple could add a minimum of three trap doors (two banks of RAM, one opening for SSDs) and maybe a door for the GPU although it would need to change the way its attached. Getting to the CPU requires full removal of the motherboard to properly remove and re-attach the CPU.
Any time you need to pay to have an iMac opened, you've lost any savings in parts cost. I know there are people who like to "customize" everything but in most cases, this is done because the person is a little bored (like @Rayz2016 mentioned) and just wants something to do other than using their computer. If Apple were to provide these access doors, I could see many more iMacs going back in for repair after people replaced Apple parts with cheap replacements from Fry's and Amazon. I trust OWC for parts but many people pay a lot for a computer (or car for that matter) and replace parts with garbage, thereby totally screwing up the initial investment. I believe this is why Apple doesn't want people opening up any of their products.
Looking at something like the iMac Pro, I would need help figuring out the proper configuration to get. I bought a fully blown iMac in 2009 and it ran great for me (with upgrades from OWC) until it didn't run the latest OS. It was easy to open up but it also had HDD failures, a power supply failure and recently a GPU failure I fixed (hopefully) by reflowing. Hardware has gotten better so I am hoping I won't have to do this with my newer iMac so what is my ideal configuration for work now and later? It would be nice for someone to put together a chart showing what applications benefit from multiple cores vs faster single cores, how much RAM is actually used by a combination of applications, and how much internal SSD is beneficial vs external RAID connected via Thunderbolt 3. Nice chart for AI to come up with.
I think they made the most powerful iMac they could, which included 4 slots with desktop-grade RAM, and there was simply no good solution go having two, very large, easily accessible RAM-doors cut into the upper and lower ends on one side (read; asymmetrical) of the primary support framework.
Note that on the standard 27" iMac it's laptop-grade RAM, it's in the center of the casing, and it's hidden behind the support arm.
This machine isn't for you. And that's OK. Say it with me: "This machine isn't for me...and that's OK..."
Ah look, another armchair thermal expert. Amazing how they're popping up everywhere!
Even the most experienced person is prone to fail because some technical documentation is only available to OEMs, and not even to those as they have to test / dissassemble / reverse engineer some part from some 3D party to get to its true performance / specs. This is no longer a job one can perform reading item description on Amazon and eBay. The stakes are high, PC repair shops are full of burnt motherboards.
Yes, people who use reason to counter your hater narrative should be called names, since you can't argue against their reasoning. Brilliant.
After having read many iFixit repair pages, this doesn't look any more difficult than a RAM upgrade on other iMacs that lack access doors, but definitely a huge chore compared to those that have them
Not likely. Based on what I've read over the years, Apple will only sell parts like this for the purpose of repairs and they will require the repair shop to send them the old (and presumably defective) motherboard afterward. If they find some service person buying parts and not returning anything, he will likely lose his authorization.
Besides, Apple should use standard parts and allow users to easily upgrade or replace them. In this case, Apple should have used better SSD like Samsung 960 Pro with sequential 3,500 MB/s read and 2,100 MB/s write, besides random 440,000 read and 360,000 write IOPS. RAID 0 is a deal breaker for our University, but imagine the iMac Pro in RAID 0 with such Samsung SSD. It would be much faster.
If Apple want to protect the environment, they should develop more headless Macs, including low, medium and high pro models because they last much longer since you just replace the Mac and kep the display, which lasts much, much, much longer than the Mac which has a maximum life of seven, years to upgrade its macOS. In such respect, the iMac a a anti-ecological.
But Apple can do whatever they want. Because people buy Macs because macOS. And thus, they are a monopoly in such respect. If you want macOS, you must buy whatever Apple does. There is no real choice and competition. And that is not good. In this case of iMac Pro they even fill all four RAM slots, so if you want to upgrade it, you must throw away DIMM, which again is anti-ecological. Not to mention that Apple RAM is two to three times more expensive that exactly the very same RAM from the same manufacturer.
But it is amazing how some people approve anything that Apple does, whatever it is. Obviously, they have vested interests. They may work for Apple, sell Apple products or get profit from it from advertisements or have Apple shares. Yet, such behavior is immoral and nonethical. Besides that, companies improve because there is competition and criticism from consumers. Positive criticism is good for all, including consumers and companies.
The more plausible answer is that this design is meant to force customers to pay for their outrageously priced RAM and to encourage early obsolescence. Aka planned obsolescence.
I was surprised to see that they had two 512GB SSD drives in a RAID0 configuration. However, as before... it doesn't matter. Your failure logic still doesn't hold. True, if one of the drives fail, you lose all your data. But guess what?? If you only have ONE 1TB SSD drive and it fails, you also lose ALL your data! Case closed. Besides, if someone truly wanted to upgrade the SSD drive, it's certainly cheaper to just install two smaller drives than one giant drive. So in the end, it's a non-issue.
I buy my Mac's, not just because of MacOS, but also because they are the best engineered systems around. They are built-like-a-tank reliable, and are the best in class.