I admit it: I didn't think it could be done.

When I heard the specs for the new iMac Pro, my immediate reaction was, "that's going to need liquid-nitrogen cooling for the 18-core model." After all, the 16-core AMD Threadripper I've been testing has been known to hit as high as 200 degrees Fahrenheit (93 degrees Celsius) when maxing out all cores on a 3D render, and that's in a roomy Alienware Area-51 desktop with plenty of airflow.

So when Apple's 10-core Xeon W model didn't break a sweat on a similar render -- and almost silently as well -- it made for an impressive demo. But the flip side was that none of its demos showed the processor running for any length of time at 100 percent utilization on all cores. That's something you're less likely to see on an Intel chip with faster clock speeds overall unless you increase the load.

No one needs to convince me about the value of faster, as-many-cores-as-you-can-get processors. I've been using a six-core Xeon E5-based trashcan Mac Pro for years. I always thought it was slow until I started testing more mainstream systems. And my use doesn't hold a candle to most real-time interaction needs.

The much-bandied-about $4,999 starting price sounds high. But for what's inside, plus the included monitor, it isn't really. (It starts at £4,899 in the UK and AU$7,299 in Australia.)

Sarah Tew/CNET

Whiz bang

I've seen the iMac Pro work its way through some pretty whizzy software demos -- including a couple of VR software applications that looked really nice, if aerobically challenging.

The first demo I tried was Gravity Sketch, a surface modeling tool that lets you manipulate control points and surfaces in VR. You can also assign materials and cameras, and basically do much of the pro 3D creation process. There's an early access version of it on Steam.

Gravity Sketch

Survios' Electronauts is a diverting virtual-club DJ-ish game. You can just have fun bopping things in VR without worrying about the specifics of music or rhythm or any kind of skill. The automation is quite well done.

And Maxon showed Cinema 4D running smoothly with high-resolution, real-time model manipulation, but more notably, they had a couple external GPUs attached to the system; support for eGPUs is new in High Sierra.

Keep in mind, however, that more cores and better GPU performance doesn't necessarily translate into a faster system. Aside from the mind-boggling arcana you have to think about when it comes to figuring where your frequently used applications will get the biggest power boost from, I also find that the bottlenecks frequently have nothing to do with the system itself.

In general, you're constrained by peripheral responsiveness, external input/output interfaces and other aspects of your workflow. Applications and operations I expected to be faster on a high-powered system simply aren't because they're optimized for fewer cores or don't run operations on the GPU yet. And you'd be surprised how little memory is used by operations you thought were memory intensive. But be warned: virtual machines are the big exception to that rule.

Important upgrades

I'm still reserving judgment on Apple's dedication to its pro graphics community. It seems like the company occasionally makes a big push to attract those users then forgets about them for years at a time then makes another push.

That said, Apple did update the iMac Pro over the iMac in an important way: The system incorporates a home-grown T2 chip (an upgraded version of the T1 in the MacBook Pro) that provides enhanced boot security and encryption. Workstation-class security is essential: You don't want to be the production company whose hacked system provided the internet with leaked "Game of Thrones" episodes. Having not tested the system yet, I can't speak to its effectiveness, though.

Sarah Tew/CNET

The handful of other hardware upgrades aren't news: There's a four-microphone array, a faster UHS-II SD card slot, a couple more USB-C/Thunderbolt connections, 10-gigabit Ethernet. Thanks to the newer, more powerful Radeon Pro graphics subsystem, it can drive more external monitors than before -- two 5K or four 4K, in addition to the built-in display.

A small but neat feature you can only get with the iMac Pro is the new dark grey versions of Apple's keyboard, mouse and trackpad. They work the same as the white versions, but you can't buy them separately.

Missed opportunities

It's nice that Apple managed to shoehorn so much power into an old design, but it would have been even better if Apple had redesigned it instead, even more so if it it paid attention to the needs of pros.

Apple talks about its iMac fans like they adore the current design and that's who they made this system for. But even diehards would like to be able to raise and lower the display or be able to use the SD card slot without having to contort around the back of the system. Apple was so proud of going bezel-free on the iPhone X. Doesn't the iMac display deserve the same attention?

Apple also added the ability for end-users to convert it to use VESA mount, normally used for hanging a monitor on the wall. But it occurred to me that it could also serve to put the system on a less stylish, more functional stand.

The Pro also incorporates the same display as the iMac. It's one of the best consumer displays I've seen, but it's still a consumer-class monitor with an 8-bit FRC panel that simulates "billions of colors." You can certainly attach multiple higher-end monitors to the system, but the whole attraction of an all-in-one's small footprint is, well, the small footprint.

Oy, the prices

Which brings me to my biggest reservation. While all-in-ones have some big advantages, I ultimately think it's a questionable idea to sink a lot of money into an all-in-one for a performance-oriented workstation or gaming system. Apple says its systems get handed down through the company ranks as they stop meeting each successive user's needs. And while that's certainly true, I doubt many accountants in large companies will continue to OK a parade of $6,000 system requisitions every two years. They're going to want to bump you down to a cheaper configuration, which means you'll outgrow it that much sooner.

Here's a sample of the prices of various configurations:

Pricing Configuration Components US UK AU Base 8 cores, Vega 56, 32GB, 1TB SSD $4,999 £4,899 AU$7,299 Maxxed-out iMac 4-core Core i7, Radeon Pro 580, 64GB, 2TB SSD $5,299 £4,949 AU$8,249 Cheapest 10-core 10 cores, Vega 56, 32GB, 1TB SSD $5,799 £6,879 AU$8,579 Apple recommended configuration 8 cores, Vega 64, 64GB, 1TB SSD $6,399 £6,159 AU$9,539 Cheapest 14-core 14 cores, Vega 56, 32GB, 1 TB SSD $6,599 £6,339 AU$9,859 My "recommended" base configuration 10 cores, Vega 56, 32GB, 2TB SSD $6,599 £6,339 AU$9,859 iMac Pro "equivalent" of iMac maximum configuration 8 cores, Vega 56, 64GB, 2 TB SSD $6,599 £6,339 AU$9,859 Apple recommended configuration 10 cores, Vega 64, 64GB, 1TB SSD $7,199 £6,879 n/a Cheapest 18-core 18 cores, Vega 56, 32GB, 1 TB SSD $7,399 £7.059 AU$11,139 Cheapest configuration with a lot of storage 8 cores, Vega 56, 32GB, 4TB SSD $7,799 £7,419 AU$11,779 Apple recommended configuration, my recommended base GPU-intensive configuration 10 cores, Vega 64, 64GB, 2TB SSD $7,999 £7,599 n/a Apple recommended configuration 10 cores, Vega 64, 128GB, 2TB SSD $9,599 £9,039 n/a Maxxed-out configuration 18 cores, Vega 64, 128GB, 4TB SSD $13,199 £12,279 $20,419

If this were a modular system, I wouldn't balk at the prices. But with an all-in-one, you really need to put in the maximum amount of storage possible because you'll run out of that quickly. Even if all your video resides on external devices, the temp files at the very least are on the fastest drive, which is local. Yes, the SSD is socketed and can be upgraded in a service facility, but you don't want someone opening it (or to have to ship it out) unless absolutely necessary. At the very minimum you want 2TB.

I also find it interesting that none of Apple's recommended configurations use the Vega 56, only the base configuration so it doesn't break the $5,000 mark. I haven't gotten a chance to test the Vega 56 vs. 64, but the fact that it's not "recommended" tells me it might not provide a base level of performance. If that's true, my base recommended configuration jumps to $7,199, £6,879 or $AU$10,819.

And I can't see spending the money on any of it, at least not now. The Xeon W might be a newly announced chip, but it's based on old Skylake-X technology. That means we'll see likekly faster workstation chips next year, especially faster chips with more cores: the reason the 10-core is the most recommended is because it's the fastest, and today's applications get the most boost more from higher clock speeds rather than more cores beyond about four.

Apple makes a big deal about being the first to make such a powerful all-in-one, but there are reasons no one else has done it.

In this case, unless you've really been waiting for an iMac, it might be worth waiting until we see what Apple's "modular Mac Pro" (which has been promised for sometime post-2017) will look like. If not, you should at least give it some time to see if Apple plans to redesign the iMac line more completely. And, of course, there's the issue of seeing how well the thermals stand up over time.

Still, I'm really looking forward to seeing how it holds up under testing as I incorporate it into my daily workflow. The new iMac Pro is available to order now, with eight- and 10-core systems shipping right away, and 14 and 18-core versions coming in January.

Comparative specifications

iMac Pro iMac 27-inch 5K (2017) Starting price (USD) $4,999 $1,799 Display 27-inch 5,120x2,880 16:9 aspect ratio 27-inch 5,120x2,880 16:9 aspect ratio Pixel density 218dpi 218dpi Color gamut 8-bit DCI P3 (with FRC dithering to 10 bits) 8-bit DCI P3 (with FRC dithering to 10 bits) Max brightness 500 nits 500 nits Processor options Intel Xeon W-2000 series 8-, 10-, 14- or 18-core Intel Core i5-7500, i5-7600/7600K, i7-7700K all quad-core Graphics AMD Radeon Vega 56 or 64, 8GB to 16GB 4GB AMD Radeon Pro 570, 575; 8GB Radeon Pro 580 Storage Up to 4TB SSD; SD card slot Up to 3TB Fusion drive or up to 2TB SSD; SD card slot RAM 32GB to 128GB 2,166MHz ECC Up to 64GB 2,400MHz Networking 10Gb Ethernet, 802.11ac, Bluetooth 4.2 Gigabit Ethernet, 802.11ac, Bluetooth 4.2 USB 3.0 Type A 4 4 USB-C/Thunderbolt 4 2 Mini DisplayPort/Thunderbolt 0 0 Additional monitors supported 2x 5K, 4x 4K UHD/Retina 4K 1x 5K, 2x 4K UHD/Retina 4K Audio Stereo speakers, headphone jack, quad microphone array Stereo speakers, headphone jack Camera 1080p FaceTime HD FaceTime HD

Update, 2.43 p.m. ET: Added pricing analysis.