Thunderbolt to PCIe drama
I just discovered this old test of 2012, whereby a thunderbolt to PCIe adapter runs external GPU at a third of a Magna or Sonnet price. Apparently, this manufacturer did not get approval from Intel, and their adapter was discontinued (although one can still be snatched off ebay as of time of this writing -- current bid is 50 pounds). Perhaps there are other low cost solutions for attaching external GPUs I am not aware of. After all, the thunderbolt to PCIe adapters from Intel cost about $70.--8
Maybe you will see it again in the future. So far the market for thunderbolt has been mac, where a thunderbolt to PCIe device shows up as a bridge and needs modified drivers to work (not the normal PCIe drivers). On a PC the cards in a thunderbolt to PCIe appeared as PCI cards directly - with the limitation of no hotswap. There are still not so many PC laptops with thunderbolt (the only market for a thunderbolt pcie card)- it may even work now, but for sure not on OSX.
I don't know: this DIY guy talks about using Titan over thunderbolt on a mac.--8
For the record: here are two better confirmed cases using external GPUs on macs.http://mediapros.co.uk/portfolio-view/thunderbolterizer/http://www.coreyrobson.com/post/52451664259/thunderbolt-gpu-is-alive-and-mostly-wellThese guys used [Quadro 4000 2GBDDR5](http://www.bhphotovideo.com/c/product/745706-REG/PNY_Technologies_VCQ4000MAC_PB_nVIDIA_Quadro_4000_for.html), [GTS450 1GBDDR5](http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/41185-sparkle-one-gts-450-1gb-oc-single-slot-review-2.html), and [GT240 1GBDDR5](http://www.newegg.ca/Product/Product.aspx?Item=N82E16814130542) cards in Sonnet and Magma boxes, and show how to modify the drivers for these cards.--8