If you spec something with similar workstation grade hardware, you'll be in the same ballpark. Gaming PC hardware isn't comparable.

Prices from newegg

    SuperMicro 5039A-i        730
    Xeon W-2145              1175
    4x8GB ECC RAM $74 x 4 =   296
    AMD Radeon RX 480         415
    SAMSUNG 970 PRO 512GB     160
    Total:                   2776

So Apple charges more than x2. And if one would use Ryzen and consumer GPU, price would be massively reduced.

The CPUs they're using are Cascade Lake, not Skylake. So I'd add at least about $500 there. You'll also need to add ~$300 for the giant 1400 watt PSU, and at least $500 for the custom cooling solution and case. Most PC cases are really not built that well.

Where did you get that $500 increase? Intel doesn't increase prices between generations, at least not that much. If anything, they could even reduce the price to have a chance to compete with new Threadrippers.

The $500 came from the new chips, plus the motherboard Apple is using is much higher spec than the SuperMicro.

It's got 8 full length PCIe slots, and two of those are the MPX slots so it's effectively 10 if you use MPX cards. It has dual 10gb NICs, and two TB3 ports.

Have a look here https://zworkstations.com/products/z840/

I tried coming up with something similar to the base spec MacPro but got larger storage, more cores and an Nvidia card with a decent saving.

It is $3000, but

>Quad-Core 2.6GHz Intel Xeon Broadwell E5-2623 v4 [4-cores / 8-threads]

We are well into Skylake era, a Broadwell is ancient comparatively speaking. The Mac Pro will be Cascade Lake, not state of the Art like EPYC with 7nm. But still a very large improvement.

>HP Z Turbo Drive Even if we choose a 256GB version of Z Turbo instead of SATA as you confined, the Turbo Drive will still be a lot slower.

>HP Thunderbolt 2 (20GB/s; one port) +$200 Yes, Thunderbolt Port are expensive. And these are only TB2, not even TB3, and still missing 3 Port.

>Intel X540-T2 | Dual-Port | RJ45 | PCIe 2.0 | 10GbE Network Adapter

Even this 2013 Dual Port 10Gbps Ethernet is a $250 upgrade.

>Wireless Mouse and Keyboard, and WiFi Added those .

So a not similar config with a very old Intel CPU cost $3475. I would imagine if you spec it exactly the same as Mac Pro, with TB3 and every hardware and ports, the HP would cost $4K+, with an ugly design. Quite a bit of saving but not as dramatic as some would imagine.

Plus, those machines are frigging awesome.

I assume this uses ECC DDR4 which would at a minimum explain some of the price tag. That will set you back $500+ retail for 32GB alone, still don’t understand where the rest is going with a 8-core CPU and a RX580X though.

It's an 8 core Xeon, plus a custom motherboard with dual 10gb, I would think that alone is probably about $2000.

I guess a 8-core Xeon W costs a cool $1K by itself, 10Gb networking isn’t tremendously expensive these days so it probably contributes $300 to the cost at MSRP. Still, $6K is too much, $4-5K would be less outrageous and still turn a healthy markup.

Yeah, I was expecting it to be either significantly more powerful than the iMac Pro or to have a lower cost for the base model. Neither of those things happened. I was willing to go out of my way to get hardware that's not quite ideal for my use case and still pay extra for it just to have macOS, but $6k is just too much. It might be expandable but each generation of Intel CPUs is incompatible with the last generations motherboards. If you care about single-core performance then it just doesn't make sense.

Maybe the case makes up most of the price?

How many people actually need an 8 core Xeon vs an i9? Almost none. And that's without taking into account how much extra you're paying just for the hardware you're getting on the base model. I was willing to compromise and pay for workstation hardware just to have macOS, but not at a 2x markup.