First of all, big thanks to Dschijn, nando, goalque and the rest for their fantastic guides!
EDIT:MUCH THANKS TO @goalque FOR THE SCRIPT TO GET THIS WORKING ON OSX!!
2014 15" MBP with Iris Pro only; i7-4770hq @ 2.2 GHz (Turbo to 3.4); 500 gb ssd
PSU: EVGA 600 B1 80+ BRONZE
GPU: Gigabyte GeForce GTX 970 Mini ITX Overclocked GV-N970IXOC-4GD
Thunderbolt 2 Enclosure: AKiTiO Thunder2 PCIE box
Cables: 2 Molex to 1 PCIE cable (to make a molex to barrel adapter)
2.5mm x 5.5 mm male DC Barrel Plug (screw terminals are the easiest)
Monitor: Dell 1920x1080
^^Not sure why there are links there...
1) Install Windows 10 via bootcamp instructions here
2) Download latest Nvidia drivers here
3) Open Akitio enclosure
4) Line up the x16 on the graphics card with the physical x16 slot on the Akitio. Push in the graphics card and screw the top screws on the Akitio to hold the graphics card steady. Plug in the PCIe 6/8 pin connector(s) from the PSU into the graphics card.
5) Make a Molex to Barrel Adapter using the 2 molex to 1 PCIE cable in conjunction with the barrel plug instructions here
As Dschijn suggested, I made the barrel plug with 2x molex instead of 1x molex by twisting together 1 yellow wire (12V) from each molex connector and 1 ground from each molex.
The yellows go in the positive terminal while the grounds go in the negative; make sure the plug is center positive!
Be sure to check polarity of the barrel plug with a multi meter to make sure it is center positive!
6) Plug in the molex to barrel adapter into the PSU's molex connectors. Apply the paperclip trick or adapter on the PSU's 20/24 pin connector
7) Plug the barrel into the Akitio's power input
8) Connect the thunderbolt cable from the Akitio into the Macbook
9) Connect the video output cable from the eGPU to your desired monitor
10) Turn on the Mac while holding "Alt"
11) When the boot selection screen appears, turn on the PSU (I use a power strip)
12) Count to 5/wait for the fans on the GPU to spin up
13) Select "Windows" on the boot screen
14) Install Nvidia drivers
15) Follow the prompts to restart the computer and what not.
The Boot Procedure that works most of the time for me:
Assuming everything is plugged in, power on the macbook while holding Alt
When boot selection appears, turn on the PSU with a power strip
Count to 5 or wait for GPU fans to spin up
Both screens should work. If not, turn everything off and try again.
I use Intel's XTU tool to undervolt and underclock its boost speed to reduce heat output. I underclocked it to 3.0 GHz and undervolted it by -75 mV. There are UV guides on the internet
I used EVGA's Precision tool to OC the Graphics card. I managed to get +190 MHz on the core clock and +350 MHz (+700 MHz effective) on the memory (probably could push further).
I also use a custom fan curve on the GPU via EVGA's Precision Tool. Temps never go above 61 degrees Celsius.
World of Tanks runs everything on Max/High 60fps @ 1080p with VSync and Triple Buffering on
Witcher 3 runs Max/High no hairworks smoothly with no noticeable drops
Naval Action (In alpha) runs everything on max no AA (kills fps in this game at this moment) @ 1080p open world and combat
CSGO obviously no problems
BF4 high in multiplayer @ 1080p and 60 fps
Warframe is smooth everywhere on Max including Physx @ 1080p and 60fps
Fallout 4 is same as above as far as I could tell
Questions are welcome even though I might not be able to answer all of them.
EDIT: Almost forgot to mention the paperclip trick
External 1920x1080 Monitor:
Heaven 4.0: Extreme settings at 1920x1080 with extreme Tess. and 8x AA
GPU OC: +190/+350
Valley: Extreme HD settings 1920x1080
GPU OC: +190/+200
SteamVR Performance Test:
+150/+200 Fidelity could be higher with a higher overclock
CPU: limited to 3.0 Ghz and undervolted by 75 mV via Intel XTU
Note: It says Iris Pro Graphics for GPU but it actually tested the GTX 970
Fidelity: High 6.2
Frames below 90 fps: 0
Frames CPU Bound: 0
Windows 10 Optimus
Heaven: same settings as above, +150/+200
~13% performance loss
Firestrike (demo version on steam):
~14% performance loss