Apple developers in select territories can now order an External Graphics Development Kit to experiment with the external GPU support coming in the next version of macOS (High Sierra) this Fall.

The company billed this $600 kit as a way for devs to "develop and test demanding graphics-intensive apps, including VR content creation, on any Mac with Thunderbolt 3 connectivity." It includes Sonnet's eGFX Breakaway Box enclosure, what appears to be a Sapphire Radeon Pulse RX 580 graphics card, a Belkin USB-C to four-port USB-A hub, and a promo code that can be used to take $100 off the cost of an HTC Vive VR HMD.

Apple developers appear to be getting early access to Sonnet's eGFX Breakaway Box; the company said on its website that the enclosure isn't currently available to purchase. Sonnet offers a variety of peripherals, ranging from Blu-ray players and storage systems to Thunderbolt accessories and enclosures, and this statement on Apple's website suggests that Sonnet will be responsible for these development kits:

For support inquiries related to any hardware components of the development kit, contact Sonnet Technologies.

That comes as a bit of a surprise, considering the development kits are being sold by Apple and include a Sapphire graphics card and Belkin hub. Not only did the company get early access to the eGFX Breakaway Box, but it's also passed off all responsibility for the development kits to Sonnet. It seems like a win-win-win for Apple--especially because the whole point of these kits is to help devs make software for its platform.

The exclusive window on the eGFX Breakaway Box makes it hard to tell if developers are saving any money by purchasing this kit from Apple. Sapphire's graphics card is currently $250 on Newegg (though it's sold out right now; perhaps because Apple bought a bunch for these kits?), and Belkin's hubs cost around $50. That leaves $300 for the enclosure, assuming the $100 promo code isn't built into the kit's cost and Apple isn't trying to make a profit on it. A similar box from PowerColor currently costs $450 on Newegg, though, so Sonnet's enclosure could be $300.

It's telling that Apple specifically calls out VR as one of the appeals of external GPUs. The company made a big push into VR and AR during WWDC, with the announcement of much-improved graphics cards heading to various Mac products, the Vega-equipped iMac Pro, and iOS 11's ARKit. Those more powerful graphics cards aren't just in there for gamers; chances are good that Apple simply wants to catch up to Microsoft.

These kits appear to be reaching developers now. Apple said on the kit's web page that the $100 promo codes for the Vive have "limited availability" and that "distribution is on a first-come, first-served basis." You'll need the developer beta of macOS High Sierra to use the External Graphics Development Kit right away. A public beta is expected to debut later this month, with the full release happening sometime this Fall.

The kit is available to registered Apple developers in these regions:

Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Hong Kong, Ireland, Japan, Luxembourg, Netherlands, New Zealand, Norway, Singapore, Spain, Sweden, Switzerland, United States, and the United Kingdom.