Pro Video and the New Mac Pro
Many people in the video-editing community are asking what the radically redesigned new Mac Pro means for them. They hear it has two AMD FirePro Graphics cards and can drive up to three 4K monitors, or that it has six Thunderbolt 2 ports and PCIe SSD internal storage. But with all that, they’re still left wondering, is it the right choice?
What it Means for Video Editors
Well, it's certainly not the “wrong choice.” It's pretty unique in terms of what it offers. No other desktop system in the same market can truly be said to compete in terms of the horsepower the Mac Pro gives you straight from the box. It is true that companies like Super Micro and HP offer professional workstations with similar CPU performance, and that these machines are easily customizable—allowing you, by adding components such as additional graphics cards and SSD storage, to bring them up to Mac Pro specs. However, these systems are targeting the much narrower market of the enterprise commercial user almost exclusively, whereas the Mac Pro, while giving you the performance and reliability of an enterprise workstation, is being sold as a mass-market consumer product. It is expected to sell thousands in a market where competitors might sell dozens or hundreds, at best.
If the idea were to cram as much power into as little space as possible, then Apple has certainly succeeded. Unlike the traditional workstation designs, where each high-energy component has a dedicated cooling system of its own (usually involving one or several fans mounted over a heat sink), the new Mac Pro has a single unified cooling system for the entire computer, including the graphics cards. This feature is the most notable innovation Apple has introduced, and not only does it enable a practically microscopic form factor in comparison to its predecessor—it measures just 9.9" tall and is 6.6" in diameter—it also cuts power consumption considerably. The new Mac Pro consumes a maximum of 450W; compare that to the 980W power supplies of the old Mac Pros. Although it may be hard to make the case that size and energy consumption are the most important features that high-performance workstation users are looking for when shopping for a computer, Apple has given us just that.
While people argue over whether the new design is stylish or looks like a garbage bin, the real question for video editors comes down to matters a tad more substantial. Aesthetics aside, the new Mac Pro is pretty standard as far high-end workstations go. Available with up to a twelve-core processor and supporting a maximum of 64GB of DDR3 RAM, it has the horsepower to meet even the most challenging post-production demands at the moment, and probably into the near future—though with technology, one never knows for sure. One thing that is still somewhat unique, even to veteran workstation users, is the inclusion of not one, but two AMD FirePro GPUs.
Dual FirePro GPUs
If there is one thing Apple has been faulted for in the past, it has been their tendency to ship wimpy graphics cards in even their highest-end systems. In Apple's defense, having a powerful graphics card has mostly only really mattered to gamers and so called “enthusiasts.” For most other uses—rendering desktop graphics, even playing back video—the stock cards did just fine since they were never asked to do much in the first place. The only time professional users really would have wanted more power was to drive multiple displays. It wasn't until hardware makers and developers realized the untapped processing potential of using GPUs to do much of the work traditionally handled by the CPU that having a strong graphics card became a factor for video editors.
That's why it may come as a surprise to many that just as GPU performance started to matter, Apple decided to release a workstation in which the GPU (apparently) can't be upgraded. In the past, the fact that the GPUs could in theory be upgraded in the Mac Pro was kind of a moot point—high-end Quadro cards notwithstanding—since next to no officially supported after-market graphics cards were ever released. Needless to say, some enterprising users attempted to find hacks to trick OSX into supporting PC-only GPUs, with varying rates of success. Apple seems to have anticipated this concern and met this challenge by offering you as much GPU processing as you could possibly want out of the box. The Mac Pro offers three GPU options:
D300: 800MHz base core clock speed, 1280 stream processors, 2GB, 5GHz (effective) GDDR5 RAM, and a 256-bit memory interface
D500: 650MHz core clock speed, 1536 stream processors, 3GB, 5GHz (effective) GDDR5 RAM, and a 384-bit memory interface
D700: 650MHz core clock speed, 2048 stream processors, 6GB, 5.4GHz (effective) GDDR5 RAM, and a 384-bit memory interface
Although branded FirePro by AMD, these cards are, in many ways, closer to the Radeon HD 7000 series cards. Of the three, the D500 and D700 options will probably be the most interesting to video editors. They offer very similar hardware specs with the exception that the D700 features 6GB rather than 3GB GDDR5 RAM. How much RAM will matter is an open question. The Radeon HD 79xx cards, to which the D700 and D700 come closest spec-wise, normally come with 3GB. At the moment, 3GB is probably more than most programs you'll want to use can even take advantage of. However, preliminary tests running Final Cut Pro X indicate that this program at least will greedily consume as much RAM as you can throw at it. Regardless of what is true right now, it is clear that as the number of GPU-aware applications spreads, we will see a corresponding increase in the amount of RAM these applications are able to use advantageously. So opting for 6GB may not be a bad investment, with an eye toward the future.
The trend toward binding the forces of GPU and CPU is known as “heterogeneous computing.” And it is this expanded application of the “graphics card” that is import to video editors. Simply to drive displays for the purposes of video playback, as opposed to rendering 3D video game graphics, isn't all that taxing. Even many consumer-grade Radeon gaming cards can power 4K displays and even drive 16K x 16K video walls made up of up to six DisplayPort monitors, thanks to multi-stream transport (MST technology). Bandwidth is actually a bigger limitation than processing power when it comes to total display resolution. It's mathematically intensive tasks, like rendering new frames of video after effects have been applied, transcoding, or creating 3D animations that can really profit from a powerful GPU—or two!
Unfortunately, GPUs aren't good at multitasking, and multi-GPU configurations are new to the OSX operating system. Certain applications, such as Blackmagic DaVinci Resolve, have been able to use custom multiple GPU configurations for a while, but there has never previously been across-the-board GPU load balancing on the Mac platform. What this means, for the moment, is that unless you are using applications written specifically with two or more GPUs in mind, one of the Mac Pro GPUs will be dedicated exclusively to driving displays, while the other handles all computational tasks. Final Cut X is, unsurprisingly, one of the few current applications that is able to distribute computational tasks across both GPUs, at least to some extent.
If you plan to run Windows on your new Mac Pro, for whatever reason, then you're in luck! The FirePros support CrossFireX, a proprietary solution from AMD, normally found on Radeon cards, which provides some degree of generalized load balancing between multiple GPUs. In general, however, effective load balancing won't be seen until software written specifically to take advantage of the dual GPU architecture gets released, or until an OS-wide, general-purpose solution is developed. In the meantime, parallel processing tasks will be sent exclusively to one card while the other sits basically idle. Does this mean that dual GPUs are a gimmick? No, but as with any new hardware innovation, it will take some time for software developers to catch up. On the bright side, video applications will probably be among the first to add support, since they stand the most to gain.
Six Thunderbolt 2 Ports
Apple has dramatically simplified I/O. You get one HDMI port, four USB 3.0 ports, and a whopping six Thunderbolt 2 ports. Having a high-speed I/O interface that offers x4 PCI Express access through an external connector is clearly a big deal—having six of them, an even bigger deal. Thunderbolt 2 offers data rates of up to 20Gb/s and, unlike Thunderbolt 1, which had to evenly split 10GB/s between data and display, the entire 20Gb/s can be used for data as long as the channel it's on isn't shared by a monitor. This provides enough bandwidth for just about any external RAID array on the market. And let's face it, if you need more hard drive bandwidth, then you probably shouldn't be using direct attached storage in the first place—a dedicated media server would be more appropriate.
Because it provides a link to the PCI Express bus, Thunderbolt also allows you to connect PCIe peripherals such as video I/O cards (“capture cards”). Increasingly, there are dedicated Thunderbolt solutions for most video I/O applications. But let’s say you have an existing card being re-purposed from your now retired classic Mac Pro. By picking up a Thunderbolt Chassis, such as the Sonnet Echo series, you can install most PCIe hardware in an external enclosure with its own power supply and use it just like it was installed internally. Many PCIe cards offer drivers for Thunderbolt support. Those that don't can often still be used by slightly altering some text in the relevant kernel extension's .plist XML file. However, if the driver does need to be hacked in this way, “hot swapping” won't be possible and attempting to do so may result in a kernel panic. To avoid an unexpected reboot, you'll need to ensure that the Thunderbolt enclosure is powered on before booting up the Mac Pro and that you don't turn it off while the computer is running.
I said before that the Mac Pro has six Thunderbolt ports. Well, there's a slight catch. The main board has three 20Gb/s Thunderbolt channels that are shared among the six ports found on the exterior of the enclosure, with two ports per channel. Therefore, you should be sure to connect devices, such as RAIDs, I/Os, and high-resolution displays that hog a lot of bandwidth on separate channels when possible.
4K—UltraHD—is here whether we are ready for it or not. And the Mac Pro appears ready. Apple officially claims the computer can support up to three 4K displays. In fact, considering a single consumer Radeon card can drive a 16K x 16K video wall through one DisplayPort 1.2 output, the Mac Pro, with the equivalent of six DisplayPort outputs plus an HDMI port and more than ample GPU power, almost certainly has the technical ability to drive even more than that. But once again, the Mac Pro has gotten ahead of itself.
If you just want to hook up a 4K TV to the HDMI port (or a Thunderbolt port using an adapter) and push out video at 24 to 30 frames per second, you're in good shape. If you need to bump the refresh rate up to 60Hz so computer graphics won't be a stuttering mess, then you'll start getting into trouble. To get 4K at 60Hz (4K60) you'll need to use Multi-Stream Transport (MST). MST is a feature of the DisplayPort 1.2 spec originally conceived to allow a single DisplayPort connection to drive several monitors daisy-chained together. MST works by splitting graphics output into arbitrary streams and offers tremendous flexibility in display arrangements, including making it possible to treat several monitors and a single display, as far as your computer is concerned, as a “video wall” effect or other non-standard display arrangement. As a workaround to get 4K60 right now, you have to send two of these streams at half 4K resolution (1920 x 2160) to a single 4K computer monitor. Unfortunately, at the moment, only a handful monitors know how to deal with MST streams in this configuration. One model that is known to work, and has been tested by Apple, is the Sharp PN-K321.
How will the Mac Pro benefit me?
Let's face it: not everyone in the video-editing community is going to need a Mac Pro—although we may all want one. A lot can be accomplished on mid-range consumer desktops or even laptops these days. The Mac Pro is for users who legitimately need a lot of power, in every sense that power has meaning in relation to a computer—from an optional twelve-core CPU, to enough space for up to 64GB of RAM, to the dual FirePro graphics cards, to three 20GB/s Thunderbolt 2 channels. The system offers as much power as you can get without building a machine yourself. And it fits in even among the most modern, stylish decor.
If you are planning on editing multiple streams of 4K RAW, if you are doing advanced color correction, or if you're creating 3D animation, you're probably a candidate for a Mac Pro. If you're editing a wedding or corporate videos shot in AVCHD and doing minimal color correction, then to say the Mac Pro is overkill is probably an understatement—most likely an iMac will serve your needs just fine. If you find yourself spending a lot of time waiting for things to render, or if you've thrown on so many effects in the time lime the footage is unplayable, the dual GPUs and 12 cores might be just what you need. At the same time, it is important to remember that simply throwing more power at the problem won't always solve the problem. If you're still editing on Final Cut 7, for example, then all of the processing cores and RAM in the world isn't going to make the program run any faster. FCP7 was written to run on ditch water because that was exactly what you needed back in the day. But today it simply can't take advantage of a more powerful machine. Once it has consumed 1.5 processor cores and 3GB of RAM, FCP7 is maxed out.
Regardless of what kind of video you are editing or grading, what really determines whether the Mac Pro is worthwhile is the software you plan to use. In general, software that we can expect to be able to exploit what the Mac Pro has to offer will be the latest, most top of the line, applications like Blackmagic Design DaVinci Resolve or AutoDesk Softimage. Authors of these kinds of programs expect you to be using high-performance workstations, because the workflow they entail requires it, and will develop their product accordingly. The question, then, is perhaps better formulated, “Will the Mac Pro benefit me when using such-and-such piece of software?” As always, it will have to be answered on a case-by-case basis.
Three 20GB/s thunderbolt 2 channels and six Thunderbolt ports: Provide connectivity for high-speed storage solutions such as RAIDs, capture cards, and displays. Thunderbolt also supports daisy-chaining of up to six devices.
Dual AMD FirePro Graphics Cards: Drive multiple high-resolution displays with support for 4K and Multi-Stream Transport (MST). Not only for monitors, the GPUs bring parallel processing to a growing number of GPU-aware applications and APIs, including many editing programs. Parallel processing results in more efficient workflows, including faster transcode times and the ability to play back video in full quality and in real time even after effects and color corrections have been applied.
Up to 12-core Intel® Xeon™ E5 processor: The CPU is still where the rubber meets the road in terms of computer performance. Decoding, rendering, transcoding, effects processing all still rely, at least to some extent, on the CPU. Having multi-core, multi-threaded processors is essential for many of today's HD and 4K productions.
Install up to 64GB of 1866MHz DDR3 RAM: More RAM almost never hurts. RAM allows more applications to run smoothly when opened at the same time. In addition, many color-correction and effects applications render preview frames into RAM, limiting the duration of playback by the amount of system RAM your computer has.