Even before the more polished products existed, people have hacked together external GPU enclosures, often interfaced to the host's PCIe bus via ExpressCard slots or ribbon cables hanging off of Mini PCIe slots. And more recently, with the interest in cramming many dual-slot GPUs onto a single motherboard for cryptomining rigs, you can find cheap, "barebones stand-alone PCIe slots" (for lack of a better term) for hanging GPUs off of. A quick search turned up a couple of examples:

https://www.aliexpress.com/item/Mini-PCI-E-to-PCI-E-1X-Expan...

https://www.aliexpress.com/item/60CM-PCI-Express-1X-To-16X-P... (Ingeniously, on this one, they've re-purposed USB 3.0 cables to carry the high-speed PCIe lanes).

The problem with all of those has always been that they only worked with an external display - there never was any way to send the image back to the laptop's own display.

LookingGlass on Linux allows displaying from other GPUs' framebuffers.

We use Resolve in VM with hardware passthrough and can monitor its display output from within another VM this way.

Apple nails the prosumer, but I really don't see many using their hardware in industry.

It actually is possible with nVidia GPU-s, but you'll be taking a huge performance hit as some of the tiny bandwidth is now used to send the rendered image back to the laptop and then to the screen.

No matter what, sending it back to the internal display is going to mean a significant performance hit. There's only so much bandwidth in a TB3 connection.

These are for mining USB 3.0 cables are the standard they have the correct number of pins for a single lane and have decent shielding.

The best resource for DIY projects in this space seems to be egpu.io. I found their guide kind of helpful: https://egpu.io/build-guides/

Here is an overview I think is helpful [1]. The sonnet eGPU-case looks like its the best value for the price. And the gigabyte box on #1 maybe if you like to buy the GPU with the box.

[1] https://egpu.io/external-gpu-buyers-guide-2018/

http://barefeats.com/ which in the Apple community is known for graphics testing of Apple products and other solutions has done a lot of work with external GPU enclosures.

One vendor (Sonnet) [1] has a 580 solution at 499. B&H has the no GPU unit at 299. So there are options.

[1]https://www.sonnetstore.com/collections/egpu-expansion-syste...

You can use this: (https://www.amazon.com/Akitio-Node-Thunderbolt3-Windows-Comp...)

It costs $250 + GPU.

One thing to note about this; it only provides 15W USB-PD. This is grossly inadequate for pretty much any laptop you'd want to connect to it, so one-plug operation isn't practical.

awesome thanks! Does that work with 1080ti? I know Apple hasn't got official Nvidia drivers but Nvidia has provided their own for a while now

Razed has a $300 alternative that is explicitly supported by the Apple ecosystem.