Revealed in June 2018, and now available to buy after years of development, the new Mac Pro is a return to form for the workstation in terms of upgradability, while also cementing its status as the most powerful desktop Mac Apple sells.
● Up to a 28-core processor
● 12 DIMM slots
● Support for 1.5TB of RAM
● Easy upgradeability of RAM, PCI-E cards, and drives
● T2 chip
● AMD Radeon Pro GPUs
● MPX Modules
● Starts from $5,999
Starting from $5,999, the baseline Mac Pro is equipped with an eight-core 3.5GHz Intel Xeon W with 16 threads, a Turbo Boost clock of up to 4GHz, and 24.5MB of cache. Other processor options include a 3.33GHz 12-core, 24-thread Xeon W with 31.25MB of cache, a 16-core 3.2Ghz version with 32 threads, and a 24-core 2.7Ghz chip with 48 threads and 57MB of cache.
At the top end is a 28-core Intel Xeon W clocked at 2.5Ghz, 4.4Ghz when boosted. Supporting 2933Mz memory, it offers 56 threads and 66.5MB of cache.
The 12 user-accessible DIMM slots are configurable with up to 1.5TB of memory, though the 24-core or 28-core processors are required to use the full amount. Given the known performance of the processor, it is theorized the Mac Pro will be able to support up to 2 terabytes in the 28-core version, based on the number of slots available.
What processors does the Mac Pro use?
According to Apple, there are five different processors that the Mac Pro will use, all within Intel's Xeon W chip family.
The base model will use an 8-core 3.5GHz Xeon W-3223 processor that can reach 4GHz under Turbo Boost, is equipped with 24.5MB of cache, and supports up to 1TB of 2666MHz memory.
The 12-core Xeon W-3235 is clocked at 3.3GHz, up to 4.4GHz when boosted, and has 31.25MB of cache. While it also supports up to 1TB of memory, it is capable of handling 2933MHz memory, improving its performance.
In the middle of the range is the 16-core 3.2GHz Xeon W-3245 capable of 4.4Ghz under Turbo Boost. Equipped with 38MB of cache, it also includes support for 1TB of 2933MHz memory.
Reaching the higher end, the 24-core 2.7GHz Xeon W-3265M can reach a maximum clock speed of 4.4GHz under Turbo Boost, and has 57MB of cache. Unlike the lower-core count chips, the 24-core model can handle up to 2TB of 2933MHz memory, though Apple rates the Mac Pro to handle 1.5TB at this time.
Lastly, the high-end 28-core Xeon W-3275M is clocked at 2.5GHz, Turbo Boosts to 4.4Ghz, and has 66.5MB of cache, with the same memory capacity as the 24-core model.
While Intel's Ark lists the cache of each processor as a lower value, it is in fact the L3 cache included in each chip. Apple's cache values are based on a combination of L3 cache and L2 cache, which can cause confusion for those looking more closely at the hardware.
Does the Mac Pro have a soldered or slotted CPU?
The modular nature of the Mac Pro has also led to another design change for Apple, namely the use of a slotted processor.
Apple tends to solder the processor to the board directly, rather than using any sort of holstering system, as a means to prevent processor changes after purchase, as well as potentially saving space by not needing the slotting mechanism. This is especially evident in the MacBook product lines, which rely on saving as much space and weight as possible.
By using a slotted processor, this mean the Xeon W can be removed and replaced by another chip. For companies, this basically makes the processor a repairable component that can be switched out for minimal downtime, rather than leaving the Mac Pro unusable and unproductive for extended periods while it goes off to be serviced by Apple itself.
Apple will likely not offer this as a service, as it has not offered an upgrade similar in over two decades. The Mac Pro 1,1 through 6,1 all had slotted processors, and Apple left upgrading the processors to users.
Where are the RAM slots on the Mac Pro?
Apple's design for the Mac Pro may at first glance seem similar to that of a typical PC, with items slotting into the motherboard, but in this case Apple is connecting a lot more components to the board than could fit onto one side. Apple's answer to that is to put some of the components on the back side of the motherboard, separate from the rest of the hardware.
A byproduct of the splitting of components is that there's also a segmentation of the cooling used. While the large fans can waft air through the main compartment, a separate blower can push air through the more confined area to cool the RAM and storage, allowing them to operate at potentially higher temperatures than the other components.
How do PCI-E cards get power in the Mac Pro?
The Mac Pro includes a total of eight PCI Express expansion slots, which can be used in a variety of different ways. Along with a half-length x4 PCI Express slot with Apple's I/O card installed, one x6 slot and two x8 slots, there is also space for two MPX bays which can provide either be used with two MPX Modules for graphics or as two pairs of a double-wide x16 and x8 slots.
Generally, the power for a card in a PCI Express slot either stems from the slot itself or can be provided from the power supply as a separate PCI-E connector with a 6 or 8-plug power header.
On to the MPX bays, each of the modules can take up to 500 Watts of power. Apple's explanation is that the PCI Express x16 slot offers up to 75 Watts of power on its own, while the extra PCIe slot has an additional connector that delivers up to 475 Watts on its own, not dissimilar to what Apple did with ADC video cards back in the G4 and G5 tower days.
There are power headers for each PCI-E slot for conventional six- or eight-pin power cabling. Labeled from one to eight, these are used to attach cables with the power header, a potentially more elegant solution than to have cables traipsing through the case from the power supply.
Why are the MPX Modules so big?
In the MPX Module, Apple has elected to create a very large and boxy casing for the graphics card. The extra size enables Apple to create a heat sink that runs almost the full length of the inside of the Mac Pro, giving considerable amounts of metal surface area for heat dissipation to occur with slower fan speeds.
Add in that the full length card can effectively channel its own private air supply from the case's front fans and pipe the air through to the exhaust at the back without coming into contact with other hardware, and it becomes an ideal cooling system that doesn't require a separate fan for the graphics card.
Do you need to use MPX for a GPU?
No. While Apple's presentation emphasizes the graphics processing of MPX modules, there is nothing stopping the use of other graphics solutions in the Mac Pro. The use of standard PCIe 3.0 connections as well as the ability to connect supplemental power via provided nearby headers means normal graphics cards could easily be used in the system.
Of course, the MPX Module method offers silent cooling, something not typically offered by off-the-shelf graphics cards equipped with their own fans. Opting for MPX cards may be quieter in general to use.
As Apple doesn't include Nvidia drivers in macOS, this does effectively limit the range of graphics cards that work to those produced by AMD. It could also be feasible to take advantage of Thunderbolt 3 to use an eGPU enclosure, though there is no real benefit to doing so since cards can be installed.
What graphics options does the Mac Pro have?
The base offering is the AMD Radeon Pro 580X, which has 36 compute units, 2,304 stream processors, 8GB of GDDR5 memory, and offers up to 5.6 teraflops of single-precision performance. This option uses only a half-height MPX Module, enabling the second PCIe slot used in full-height modules to be available for extra expansion if required.
At the higher end is the AMD Radeon Pro Vega II, which has 64 compute units, 4,096 stream processors, 32GB of HBM2 memory, and 14.1 teraflops of single-precision performance.
An alternative option is the Radeon Pro Vega II Duo, which has two Vega II GPUs working together on the same card. This gives the Mac Pro 128 compute units, 8,192 stream processors, 64GB of HBM2 memory, and single-precision floating-point performance of up to 28.3 teraflops.
As there is space for two MPX Modules in the Mac Pro, there is the extremely high-end option to have two of the Radeon Vega II Duo modules installed, providing four GPUs. As there are also standard PCIe slots available, it also means off-the-shelf graphics cards could be used, though Nvidia cards are not supported in macOS at this time.
Why does the Mac Pro have PCI-E 3.0 instead of PCI-E 4.0?
According to Apple's technical specifications for the Mac Pro, it includes eight PCI Express expansion slots, but all are described as being "gen 3," otherwise known as PCIe 3.0. The connection has been a widely-used industry standard for years, and the addition to the Mac Pro isn't entirely surprising.
So far, there are no Xeon processors that support PCI-E 4.0 or the even newer 5.0 expected until the first half of 2020, far too late for inclusion in the fall Mac Pro release.
Given the time it takes to design a new system and upgrades, Apple may even want to wait until 2021 before it makes any PCIe changes. "Sapphire Rapids" follows Ice Lake and is tipped to include support for PCIe 5.0, which could be a much better prospect for a performance-focused Mac.
Mac Pro internal cooling
As part of the design of the Mac Pro's enclosure, Apple created air inlets and outlets to provide as much airflow as possible while simultaneously keeping the casing as rigid as possible. While typical case producers would use holes stamped out of sheet metal, Apple went for a different approach.
Citing that it is based on a "naturally occurring phenomenon in molecular crystal structures," Apple says that the pattern is made up of hemispheric divots drilled in to each side of the panel. Drilled at an offset, the majority of the hemispheres intrude into space cut away by three hemispheres from the opposing side, creating the pattern of holes.
The result is an enclosure that has an extremely large surface area for airflow, more than that of the original Mac Pro. This allows vast amounts of air to pass through with a more laminar flow to the inlet of the fans than thousands of smaller holes, and maintains the structural rigidity of the enclosure at the same time.
It also helps considerably lighten the case as well, since the lattice creates areas that are made up of "more air than metal," as Apple puts it. This and the weight reduction is why the same technique is used on the back of the Pro Display XDR.
How do you open up the Mac Pro?
On the top of the housing, in between the frame's handles, is a large latch. This semi-circular handle can be lifted up and twisted a quarter-turn between two positions, marked on the top of the case and within the latch cavity.
Once twisted to the unlocked position, the latch handle can be used to lift the entire external casing up and off the Mac Pro.
Replacing the enclosure is simple, consisting of lowering it around the Mac Pro, then twisting the latch a quarter turn to its original position.
What is Apple's Afterburner card
Afterburner is a card for the Mac Pro that is designed for use in video production. Rather than relying on the processor or graphics cards for some tasks, the Afterburner takes over for some tasks, specifically those relating to video processing between formats, freeing up the rest of the system components to perform other tasks.
When fitted into a Mac Pro's PCI Express x16 slot, video editors will be able to manage high-resolution, high-bitrate videos with ease, without any of the stuttering or waiting that could occur in less-powerful systems. The smoother the workflow, the easier for the editor to work, and the faster they can complete the video project.
On a more technical level, the Afterburner is a card with what Apple refers to as a Field Programmable Gate Array (FPGA), or a programmable Application-Specific Integrated Circuit (ASIC). This effectively means it is a card that has chips created for a specific task, rather than a general-usage chip.
While graphics cards offer the ability to perform computing tasks, they are still using chips that are "general" in usage, albeit within the field of graphics. They can be used for a variety of tasks, which makes them flexible, but not necessarily able to offer optimal performance compared with a made-for-purpose chip.
The card is built to accelerate ProRes and ProRes RAW codecs, namely the encoding and decoding of the codecs, which is a processing-heavy task in most cases. Apple claims the card is capable of handling up to six streams of 8K ProRes RAW video simultaneously at 30 frames per second, making it extremely useful for video editors working at the highest possible level.
On less demanding video specifications, it is able to work on up to 23 streams of 4K ProRes RAW video at 30 frames per second, or at 4K ProRes 422, up to 16 video streams.
In terms of compatibility, Apple advises it will work with ProRes and ProRes RAW codecs in Final Cut Pro X, QuickTime Player X, and "supported third-party apps," though at this time it is unclear what these will be.
What does the T2 chip in the Mac Pro do?
The Apple T2 Security Chip is a separate processor that for some aspects of operation sits between whichever main Intel processor your Mac has, and macOS.
It sits there to ensure, first of all, that nothing can ever get loaded onto your machine without you explicitly wanting it to. The T2 chip provides a secure boot, which means that the only things that can run at start up is trusted, approved macOS software.
This prevents malware getting its hooks into your Mac when it starts up, and the T2 chip also takes care of security once it's running. For instance, built into it is a dedicated Advanced Encryption Standard (AES) hardware engine. This makes sure the data on your storage drives is encrypted and because it's done in hardware, there's no hit to the speed of your Mac as macOS reads and writes data.
The T2 chip includes an audio processor that is meant to contribute to an overall superior sound quality, compared to Macs without it. In practice, though, musicians have reported problems.
What Apple does not mention in its official T2 security documentation is that video encoding is also faster with T2.
In trying to document it precisely, we found there were multiple factors and what you saw depended on what video software you were using.
However, the difference could be in the order of many minutes for the Mac Pro. Using the right settings, a T2-enabled Mac will typically encode video significantly faster than a machine without the T2.