[hendersoon]

Sadly, the blocker for external graphics isn't the power draw, it's that Intel steadfastly refuses to license Thunderbolt for external GPU enclosures.

That's why you can't buy a macbook air and plug in a little $300 box with a GeForce 970 and play high-end games on it right now. There are no technical reasons why this won't work-- in fact, people have hacked together solutions that work great.

Intel doesn't want to let you do it.

[mikhailt]

Not anymore with TB3:

From: http://www.anandtech.com/show/9331/intel-announces-thunderbo...

>>> Meanwhile gamers will be happy to hear that Intel is finally moving forward on external graphics via Thunderbolt, and after more than a few false starts, external GPUs now have the company’s blessing and support. While Thunderbolt has in theory always been able of supporting external graphics (it’s just a PCIe bus), the biggest hold-up has always been handling what to do about GPU hot-plugging and the so-called “surprise removal” scenario. Intel tells us that they have since solved that problem, and are now able to move forward with external graphics. The company is initially partnering with AMD on this endeavor – though nothing excludes NVIDIA in the long-run – with concepts being floated for both a full power external Thunderbolt card chassis, and a smaller “graphics dock” which contains a smaller, cooler (but still more powerful than an iGPU) mobile discrete GPU.

[grecy]

Slide #15 in the presentation actually has "External graphics" as a bullet point, so maybe that's about to change?

[hendersoon]

So it does! I hope you're right, that would be amazing!

[unfamiliar]

I suspect this is because they think thunderbolt 1 and perhaps even 2 do not have the bandwidth to give satisfying graphics performance. This might change with thunderbolt 3.

[masklinn]

TB1 and TB2 might not have had enough bandwidth for high-performance stuff but it did have more than enough bandwidth to blow IGPs out of the water: DYI external TB2 systems had 80~90% of "internal" desktop performances on synthetic benchmarks[0], even with a TB — EC chain you could reach very, very respectable performances[1]

[0] http://www.anandtech.com/show/7987/running-an-nvidia-gtx-780...

[1] http://forum.techinferno.com/implementation-guides-apple/427...