Retina 5K iMac vs. Mac Pro: Which Mac powerhouse should you get?

How to pick the perfect Retina 5K iMac or Mac Pro for you!

Apple has two pro-level Macs on the market: iMac with Retina 5K display and Mac Pro. The first is an all-in-one with the best screen in the business, the second a mini-tower with massive graphics potential. But which one should you choose?

iMac 5K

iMac comes in 21.5 and 27-inch sizes, but if you're going pro, you're going big. That means 5120 x 2880 resolution. That's 14.7 million pixels in total, so many that Apple needed to develop its own custom timing controller to get the screen to work right. It also showcases the full DCI-P3 color space, which is the same as the color space used in digital movie theaters, and 25% wider than the previous generation sRGB gamut.

The 5K display is aimed at content creators and others working with truly high-definition, high-resolution source material. You can edit a 4K movie on the Retina iMac at full resolution using Final Cut Pro, for example, and still have enough space left over to see tools, timeline and clips.

The Retina 5K iMac is also Apple's fastest iMac model: It comes in three base configurations: The $1,799 model sports a 3.2 GHz Intel Core i5 "Skylake" processor paired to AMD Radeon R9 M380 graphics, 8 GB RAM, and 1 TB hard drive. The $1,999 version sports a 3.2 GHz Intel Core i5 "Skylake" processor paired to AMD Radeon R9 M390 graphics. It comes with 8 GB RAM and a 1 TB Fusion Drive. The $2,999 version sports a 3.3 GHz Intel Core i5 "Skylake" processor paired to AMD Radeon R9 M395 graphics.

The iMac includes four USB 3 ports, two Thunderbolt 2 ports, Gigabit Ethernet, headphone port and SDXC card slot. Bluetooth 4.0 and 802.11ac Wi-Fi are also built in.

Build to order options go up to a 4.0 GHz Intel Core i7 "Skylake" processor, AMD Radeon M395X graphics, 32 GB of memory, a 3 TB Fusion Drive or 1 TB flash drive.

Mac Pro

The latest iteration of the Mac Pro began shipping shortly before the end of 2013. It's a very different computer than the iMac. It's shaped like a turbine, and it's "headless" — that is to say, it has no built-in keyboard or display. The turbine shape was designed to wick heat away from a unified thermal core; inside the Mac Pro, many of the major heat-generating components face inwardly, where quiet fans draw cool air through the base and expel warm air out through the top to keep things cool.

The Mac Pro has been built from the ground up for speed. Outside of the fans, there are no moving parts inside: Everything is solid state. The system comes equipped with Flash storage only, there's no internal hard disk drive.

On the back of the Mac Pro, you'll find 4 USB 3 ports, 6 Thunderbolt 2 ports, two Gigabit Ethernet connectors, an HDMI port, combined optical digital audio output/analog line out minijack and headphone jack. Bluetooth 4.0 and 802.11ac Wi-Fi are included.

The Mac Pro comes in two, recently updated configurations: a $2,999 3.7 GHz 6-core system with 16 GB RAM and dual AMD D500 graphics processors, and a $3,999 3.5 8-core system with 16 GB RAM and dual AMD D700 graphics processors. Both come standard with 256 GB of Flash storage.

Configure to order options include a 12-core processor; up to 64 GB RAM; and up to 1 TB of flash storage.

5K vs. 3x4K

The Retina iMac's 5K screen is the biggest display in the Mac world: 14.7 million pixels, four times the size of the other 27-inch iMac screens. And it's simply gorgeous. Black blacks, brilliant colors, sharp contrast, and with DCI-P3, the highest color gamut Apple has ever shipped. Even small typography is readable on the screen — more like looking at print than seeing a monitor. It's truly a thing of beauty to behold.

But even that isn't enough for some of us. Apple allows you to connect two more screens to the iMac, thanks to Thunderbolt 2. The Retina iMac can accommodate up to two additional 2560 x 1440 displays, or one additional 5120 by 2880 display using dual-cables, turning your iMac into a multi-monitor monster.

The Mac Pro doesn't have a built-in screen, but it does have gobs of expansion ports. There are a total of six Thunderbolt 2 ports on the Mac Pro, three times as many as the Retina iMac, and each of them can be used to drive a Thunderbolt Display. There's also an HDMI 1.4 interface, which can connect a 4K television.

You can have a total of six external screens connected to the Mac Pro at once, working at standard resolution (defined as the 2560 x 1440 resolution of a Thunderbolt Display). If you work in 4K, you can have three 4K displays hooked up to the Mac Pro instead.

Of course, that means you're actually going to have to buy external displays for your Mac Pro, which will add to the expense of setup. How much you want to spend is entirely up to you.

In terms of raw numbers, the Mac Pro wins this round. But the iMac's internal 5K display really sets it apart from any other Mac right now, and it's absolutely worth checking out.

Sixth-gen Core vs. Xeon: Which Mac has the better processor?

The Retina iMac comes equipped with a variation on the sixth-generation Intel "Skylake" processor, either Core i5 or, in higher-end and build-to-order configurations, Core i7.

The base model Mac Pro uses older Intel's Xeon E5 processors. It's a heavier-duty processor aimed at server operations.

Xeon chips have gobs of L3 cache, which can greatly speed up operations. They're designed to run cooler at high load, and they also support a special type of memory called Error Correcting Code (ECC) that's better for computational operations where you can't afford any sort of error: Scientific work, for example.

Quad-core means the processor is capable of doing four times the work for applications that make use of multithreading technology, and that encompasses a wide swath of what your Mac does in the course of a day. The more cores the Mac has, the more efficiently it can perform some tasks that are optimized for this sort of CPU.

Practical examples include encoding video, compressing and decompressing files, compiling code and many other operations. Parallel processing is so integral to OS X that Apple developed a core technology built into OS X called Grand Central Dispatch, which it uses to manage multiprocessing operations.

The Mac Pro comes in two basic configurations for $2,999 and $3,999: One has a six-core Xeon processor, while the other has an eight-core Xeon processor. If parallel processing performance is important to you, you can drop even more money to take the Mac Pro up to 12 cores. Clock speed goes down as you start piling on more cores, but the assumption is that you can get more done with more cores, if you're using multithreaded apps and ones designed for multiple core machines.

In the end, these are two thoroughly different classes of computer. The iMac's "Skylake" underpinnings are incredibly powerful and it excels at single thread operations. But the Mac Pro is a parallel processing monster that's designed for more specialized work than the iMac.

Graphics: AMD Radeon vs. AMD FirePro

The 2013 Mac Pro and the Retina iMac both come with graphics processors manufactured by AMD, though they're very different. While both are powerful, the Retina iMac's is squarely a consumer-class product. The Mac Pro's is a workstation processor. Well, dual workstation processors, more specifically.

The Retina 5K iMac sports AMD's Radeon R9 M380, R9 M390, and R9 M395 processors. These chip was designed for laptops. The iMac has long used power-efficient and heat-efficient parts because of its small internal dimensions. Having said that, it's AMD's top-of-the-line mobile graphics processor, aimed at consumers looking for the best possible performance and experience out of their system.

The Radeon R9 M300 series uses the same Graphics Core Next (GCN) architecture as AMD's other premium graphics processors, both for mobile and for desktop. While it's aimed squarely at gamers, it also has practical applications for parallel computing, just like the graphics processors found in the Mac Pro — it's Open Computing Language, or OpenCL-compatible and designed to enable developers to access the compute power of the graphics chip for scientific visualization, engineering and other applications.

The Mac Pro touts AMD's FirePro D500 or D700 graphics processors, depending on configuration, and not just one, but two. FirePro graphics aren't aimed at consumers — they're workstation graphics cards. They can handle digital video editing at 4K while applying visual effects, for example, or manipulating huge 3D models.

What's more, FirePro graphics are designed for more than just general use — they're also parallel-processing pipelines of their own. For apps that use OpenCL — data visualization tools, tools used in science and research — the FirePro graphics chips can be a tremendous boost.

There's no question that the Mac Pro has more powerful and more flexible graphics processing units than the iMac, but just as with the CPU, both systems are custom tailored to different uses.

Storage: Fusion Drive vs. pure SSD

The lower-end Retina iMac comes stock a 1 TB hard disk drive, the same kind you'll find in the other iMacs. The higher-end version has a 1 TB or 2 TB Fusion Drive. The Fusion Drive combines a 128 GB PCI Express-based Flash drive with a 1 TB or 23 TB hard disk drive; they're linked together to create one logical volume that's 2 TB or 3 TB. The combination means much quicker boot speeds, application launching and document loading than a hard drive alone.

Under normal circumstances, you'll get all the benefits of flash storage and the benefits of large capacity: faster boot times, quicker application load times, less time spent waiting for stuff to load or save to hard disk, plus 1 terabyte to work with. If you've never used a Fusion Drive before, you'll be surprised at just how peppy it is.

If 2 TB isn't enough, you can upgrade it to a 3 TB Fusion Drive. You can also go pure SSD if you want, up to 1 TB of flash storage in total.

Be warned though, once you go SSD, you can't go back. Even Fusion drives feel slow by comparison. Especially when you hit the HDD part of the fusion. And you will.

Speaking of pure SSD, that's all you'll find on the Mac Pro. The Mac Pro's only moving part is its fan. Oddly, you can't configure it with anything close to the capacity of the Mac mini—1 TB is as large as it gets inside. Apple says that's not that big a deal because of all the Thunderbolt 2 ports, but installing external storage will bulk up your configuration.

Who should buy the Retina 5K iMac?

The Retina 5K iMac is a stunning piece of engineering. It's sleek, fast, and has the best-looking display of any Mac in circulation. Under the hood it has the right balance of power and performance for anything you can throw at it, whether it's editing video in 4K, editing photos, playing a video game or just working in Microsoft Office or iWork.

The first Mac capable of displaying 5K video is in a league of its own right now, a distinct and unique offering that shares the outward trappings of the other computers that share its namesake. It's not for everyone — most people can spend way less money on an iMac and get an eminently capable computer that will keep up with them no matter what they do.

Apple's made the Retina iMac more affordable at $1,799. I'd strongly consider spending the extra money to get the faster processor and Fusion Drive.

Buy now from Apple

Who should buy the Mac Pro?

Apple aims the Mac Pro squarely at the same sort of digital content creators who can benefit from the iMac — people working with digital video (4K or otherwise), digital audio engineering, people who spend all day in Photoshop or other image editing software — all the traditional strengths of the Mac platform.

The Mac Pro has plenty of applications beyond that, however. It's a fantastic machine for engineers, architects, and others working with 3D visualization and design. Its parallel processing-optimized architecture also makes it superb for scientific work too.

The Mac Pro may not be able to display a 5K image, but it can run multiple 4K displays or even more lower-resolution monitors like Apple's Thunderbolt Display. That, combined with its all solid-state design and processor and GPU options that can take its performance to the stratosphere, make it a formidable option for anyone looking for Mac powerhouse.

Of course, all this power comes at a price. The base Mac Pro is significantly more expensive than the Retina iMac, and customizing it with faster processors, more storage, more memory and a better GPU can send the price really high. But for the Mac user who absolutely wants performance without compromise, the Mac Pro is the machine to get.

Buy now from Apple

But... but... updates?

Totally fair. Apple has been updating iMacs fairly regularly, adding 5K in 2014 and DCI-P3 in 2015. Last year came and went without a new iMac, but Apple has indicated a pro-level refresh is on the way. If you need something now, our recommendations stand. If you can wait, always wait as long as you can and then buy with no regrets.

Mac Pro is another story. Apple hasn't really updated them since 2013. Even the current configuration updates are just that — configuration updates rather than real refreshes. Apple has indicated that a new Mac Pro is coming... but not this year. So, if you really need massively parallel processing and you need it on a Mac, get a Mac Pro now. If you can wait and see what comes next, wait and see.

Still undecided?

If you need extra help, feel free to ask. What's more, we have separate discussion forums dedicated to the Mac Pro and the iMac; you're welcome to pop in there for more help.