Does Thunderbolt I/O Have a Place in CAD Workstations?

30 Oct, 2014 By: Alex Herrera

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It's a name that's not often on the tongues of IT managers searching out new hardware technologies for CAD. Thunderbolt input/output (I/O) technology has been gaining visibility, however, and working its way into Windows and Linux workstations. That emergence raises the obvious questions for CAD professionals: What does it offer? Do I want it? The answer to the former is clear, but the answer to the latter is more variable.

For mainstream applications, a PC's I/O functions might be limited to trivial-demand devices, such as keyboards and mice. But a workstation's I/O ports access higher-bandwidth external devices including hard drives and video capture equipment, making an emerging, high-performance standard like Thunderbolt worth a look. Thunderbolt's roots lie in an advanced development project at Intel called Light Peak, first unveiled in 2009. Employing optical I/O technology instead of traditional metal (i.e., copper) interconnect, Light Peak technology promised a huge jump in I/O bandwidth, pushing toward 100 Gigabits per second (Gb/s) over the next decade.

What made the technology compelling was not just its performance, but its ergonomics. Without the tight length restrictions mandated by signal attenuation over copper, each cable could get much longer (not to mention a lot thinner). And Light Peak supported daisy-chaining, meaning one cable could replace the multiple, disparate cables we have today.

A particularly valuable feather in Light Peak's cap was its ability to concurrently support PCI Express and DisplayPort connections over the same cable. That means one (or more) of those daisy-chained devices can be displays, further unifying I/O and streamlining the desktop. With lower cost, higher bandwidth, compatibility for multiple protocols, longer cables, and simpler connectors, Light Peak was looking like a game-changing advancement in I/O.

Falling Back to Copper

Wait, Thunderbolt's an optical technology? No, that part of the vision has not come to pass, unfortunately. Optical I/O technology wasn't — and most would argue still isn't — ready for high-volume applications.  And when one particularly high-profile company stepped up with a high-volume interest in Light Peak, with a far shorter timeframe in which to deliver it, Intel compromised on its optical-or-bust goal. Apple was anxious to differentiate itself with a new consumer-friendly interconnect technology, so it teamed up with Intel to create Thunderbolt, based on Light Peak but sticking with tried-and-true copper as a physical layer.

Intel’s Light Peak optical I/O, circa 2009: the original vision that spawned Thunderbolt. Image courtesy of Intel Thunderbolt Technology Community.

Thunderbolt soon found its way across Apple's Mac lineup. While Thunderbolt continues to support an optical physical layer in principle, today essentially all Thunderbolt implementations are with copper cabling. While copper falls far short of optical's bandwidth levels, Thunderbolt retains much of Light Peak's envisioned ergonomic advantages, including daisy-chaining and PCIe/DP concurrency.

The Expanded Appeal of Thunderbolt 2

The first generation of Thunderbolt was slow to catch on beyond Apple, as scant few applications or devices materialized to drive broad-based demand or support for Thunderbolt among the PC and workstation communities. Yes, first-generation Thunderbolt's 10 Gb/s rate delivered a nice bump in throughput, but it turned out USB 3.0's 5 Gb/sec was pretty darn fast for most I/O needs.

It's a different story with the second generation, however, both in terms of the technology's appeal and its current acceptance, proven courtesy of the Mac. Thunderbolt 2 touts an impressive 20 Gb/sec of serial bandwidth, which it delivers by combining two of the existing 10 Gb/s channels. Now, we're not talking just a twofold increase over USB 3.0, but fourfold. That's more of an eye-catching figure for workstation users that demand both capacity and speed, particularly since it supports simultaneous 4K capture and display. It's also helped move HP, Dell, Lenovo, and Fujitsu to support Thunderbolt 2 in their recent workstation product refreshes.

Of course, an interconnection technology is only as useful as the things it connects. So what devices can Thunderbolt 2 support for a CAD-focused workstation user? Connecting to a workstation display doesn't have the same appeal that it does in the Apple space. Workstation add-in cards and motherboard graphics processing units (GPUs) all support DVI, and increasingly DisplayPort, as standard interfaces, making Thunderbolt for monitors non-essential (and not very well supported). And while high-definition, 4K video capture is of intense interest for video editors and broadcast studios, it's of limited value in typical CAD workflows.

Daisy-chainable and 4K video capable, the second generation of Thunderbolt comes to workstations. Image courtesy of Intel Thunderbolt Technology Community.

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About the Author: Alex Herrera

Alex Herrera

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