People who are speculating how many arms, legs, vital organs, first born children, etc. they will have to sell to buy a maxed-out one of these bad boys are forgetting a very crucial detail, perhaps due to the fact that they have been conditioned by Apple's solder-based ecosystem for the better part of the last ten years: Pretty much everything in this machine is socketed. Nothing, aside from the T2 chip, is soldered in, which means for the first time in nearly a decade, you finally can do something with a Mac that's actually pretty neat:
YOU CAN PIECE-MEAL THIS THING!
That's right, you can buy certain parts right off the bat, and buy other parts at a later date. And that's how you
should do it. Nobody should be buying overpriced RAM from Apple, let alone 1.5 TB of it. Based on iMac Pro math (4x64 GB RAM modules = $5200), expect 12x128 GB RAM modules to run up to $30,000 for the RAM alone, if not higher. According to the press release from Intel, the Xeon W-3275M (Let's assume this is the same 28-core SKU used in this Mac Pro, not a binned version) will cost $7453.00 at launch, so with the Mac Tax, expect Apple to charge close to $10,000 for that CPU alone. I, personally, am not in the market for this machine, but if I were, here's how I would go about getting it:
At launch:
From the Apple Store, I would slightly upgrade the base configuration like this (bear with me, there's a method to my madness):
Upgrade the base 8-core Xeon to the next-tier up, the 12-core Xeon, since the 12-core Xeon supports RAM speeds of 2933 mHz, whereas the 8-core Xeon only supports RAM speeds of 2666 mHz.
Stick with the base-tier configuration of RAM from Apple, and buy 12 modules of this RAM for about one-fourth to one-third of what Apple will charge for 384 GB of RAM:
https://www.crucial.com/usa/en/ct32g4rfd4293
Upgrade the GPU to a
single Radeon Pro Vega II Duo MPX module, do
not buy two MPX modules at launch. Based on what I'm gathering, you will most likely be able to get a second one of these bad boys separately down the road, and possibly significantly cheaper when that time comes, but more on that in a bit.
Oh, just get that Afterburner, live a little! Probably will end up being one of the least-expensive components in this rig.
Max out the SSD configuration to 4 TB. If you do a lot of 4K, 5K, 6K, and/or 8K video projects, you will fill that up quick, unless you can find a lot of TB3 external storage on the cheap.
Now you're done with your launch configuration. This should tide you over for the next 2-3 years.
Down the road:
Hopefully, the 28-core Xeon W-3275M will come down in price after a couple of years of bring on the market, and you will be able to get one off eBay for potentially thousands of dollars less than what you would have paid Apple at launch.
RAM has been getting cheaper and cheaper over the past couple of months, and if those trends continue over the next 2-3 years, at least with regards to 2933 mHz ECC DDR4 RAM, you should be able to get 1.5 TB for nearly the same price you paid for the Crucial memory I linked earlier.
You will most likely be able to buy a second Radeon Pro Vega II Duo MPX module off eBay in 2-3 years for a fraction of what you would have paid for it at launch. And there's a good chance you can find one of these in a "Like New" condition, if not straight-up "New/Never Used".
Now, you've got a maxed-out 2019 Mac Pro for tens of thousands of dollars less than what you would have paid Apple to max out at launch. You're welcome.