The iMac Pro, is Apple’s most powerful iMac to date. It comes with either a 3.2 GHz 8 core, 3.0 GHz 10 core, 2.5 GHz 14 core or 2.3 GHz 18 core Xeon W processor. EMC 3144 / A1862 (ID iMacPro1,1)
The additional cost to get the 128gb of RAM on this system is astronomical. If I buy one with the default 32gb RAM, will I be able to crack this thing open down the road and install 3rd party RAM if I want to expand?
Details:*Apple reports that this iMac Pro supports "up to 128 GB of quad-channel 2666 MHz DDR4 ECC memory." By default, it ships with four 8 GB memory modules. At the time of purchase, Apple also offers to configure this model with 64 GB or 128 GB of RAM for an extra US$800 or US$2400, respectively.
Here are the kits available from OWC to do a RAM upgrade:
We'll need to wait for the IFIXIT teardown to understand more fully what is needed to replace or upgrade the RAM. I'm sure you have other questions on the SSD and general serviceability of this system. This system does not have an access door like the other 27" models.
Per Apple's notes: "The RAM can be serviced by a qualified Apple technician".
Now consider when you plan to add the RAM. Most people won't need more than 32 GB. Which gets into the systems warranty and if you void it by doing it your self, I would hold off until the warranty has expired. If you are doing this sooner, have Apple or Apples certified service techs do it so you don't loose coverage. Given the price of this system I would caution you doing this your self as it could be a very expensive Oops!
Watch this video it’s the third of three but you can probably locate the other two if you wanted…It will give you a look at what’s in the box and some colourful commentary….https://youtu.be/EdwDvz47lNw
But the hard part is getting to the memory. Apple might have considered this when they designed the layout. It should cost you about $300-$350 in labor + $350 for 64GB of memory. Good luck!