Thunderbolt expansion devices beginning to crop up

Thunderbolt-based devices that offer numerous expansion possibilities are beginning to show up for Mac systems.

Topher Kessler MacFixIt Editor
Topher, an avid Mac user for the past 15 years, has been a contributing author to MacFixIt since the spring of 2008. One of his passions is troubleshooting Mac problems and making the best use of Macs and Apple hardware at home and in the workplace.
Topher Kessler
2 min read

In the wake of the announcement by Sonnet for its Thunderbolt-based Echo ExpressCard adapter that will allow any compatible ExpressCard to work on a Thunderbolt Mac, peripheral developer Magma has announced a Thunderbolt-based expansion chassis for full-size PCI Express cards that will accommodate anything from audio cards, modems, and connectivity peripherals to video cards for additional displays.

According to a press release, the Magma "ExpressBox 3T" will hold up to three PCI Express cards side-by-side to offer any Thunderbolt-equipped Mac the option to add more functionality, even if the Mac does not have any built-in expansion ports, which includes iMac, Mac Mini, and MacBook (Pro) systems. If you are looking to add expansion ports to your system that Apple does not offer (USB 3, or eSATA), then this may be a great option to have. Additionally, it will allow you to add audio interfaces and even multiple video cards for added video processing power.

Magma ExpressBox 3T
The ExpressBox 3T will hold up to three PCI Express cards, and attach them to your Mac with a Thunderbolt cable. Magma

Magma is a company that has specialized in offering expansion PCI and PCI Express units for computer systems, including internal solutions, and rack-mountable expansion chassis. The PCI Express options it has provided in the past have required an available PCI Express slot, but since Thunderbolt carries PCI Express on its bus, all you need is this port on your system, which Apple is building into every one of its Macs. The chassis contains PCI Express 2.0 slots, its own 220W power supply, and supports daisy-chaining so you can have up to six of them in line on your system, if desired.

This is exactly the kind of device to take advantage of Apple's Thunderbolt technology, but do keep in mind that the 10Gbps speed limit for Thunderbolt does limit some of its capabilities for now. While Thunderbolt's specification offers up to 100Gbps speeds, it is currently limited to a tenth of that for compatibility reasons. This is also about 1/12 of the speed of the internal PCI Express bus that is used for high-quality video cards and other expansion cards that require heavy throughput. Despite this, many cards will work just fine on the slower bus.

The development of these expansion devices is great news for Mac users, and we are looking forward to seeing them bring new expansion possibilities to Mac systems that do not have options for internal expansion cards. Magma's option is the first to allow the versatility of providing any Mac-compatible PCIe expansion card, but Sonnet has also mentioned it is working on similar external expansion devices. According to MacTech, Sonnet already has a new rack-mount server chassis for Thunderbolt Mac Mini systems that includes an external PCI Express slot.

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