One month ago, i've started my first eGPU project. I was looking for a solution to improve my render times. I've searched the web for possible solutions and i found this site. After two days reading a lot of articles in this forum, i've made my decision. So i started a new thread "eGPU with IMac 21" 4k (late 2015)" in the section "Apple eGPU discussion" and wrote down my questions. Within a few hours, I've got all the answers i needed (many thanks to @Dschijn! Without his recommendations, gain experiences and hints, i never would be able to build my egpu). When i finished my first part of my egpu project, Tech Inferno Fan asked me to post an implementation guide.
So here is my implementation guide:
Because i want to speed up my render times, i needed an GPU with a lot of CUDA cores. So i decided to built up my eGPU with a high performance GTX 980 TI.
iMac (Retina 4K, 21.5", Late 2015)
3.3 GHz Intel Core i7
1TB Fusion Frive HDD
16GB 1867 MHz DDR3 RAM
The components, I bought:
Akitio Thunderbolt2 PCIe Expansion Box MP-TB-PCIE ( https://www.format.de/Products/5961/index.php?gclid=CPDWsYn2hsUCFUblwgodMa0AVA)
ASUS STRIX GTX 980 Ti (http://www.hiq24.de/shop//GeForce-STRIX-GTX980TI-DC3-6GD5-GAMING,-Grafikkarte/170245/100/i.html?)
PSU: Thermaltake Smart SE 630W (http://www.hiq24.de/shop/Hardware/Komponenten/Netzteile/ab-500-Watt/Smart-SE-630W,-PC-Netzteil/81758/9512/i.html?)
24-Pin ATX adapter (https://www.caseking.de/bitspower-24-pin-atx-ueberbrueckungsstecker-zuad-083.html)
DC cable (http://www.reichelt.de/DC-AKS-7525/3/index.html?&ACTION=3&LA=446&ARTICLE=150126&artnr=DC+AKS+7525&SEARCH=niedervoltstecker+2.5mm)
MOLEX adapter (http://www.reichelt.de/DELOCK-82315/3/index.html?&ACTION=3&LA=446&ARTICLE=143815&artnr=DELOCK+82315&SEARCH=6-pin+pcie+kabel)
Within a few days, i have got everything, i need.
I've opened the AKiTiO. I bend the back part of the case a bit because the GTX980TI is to long.
I put the GPU into the PCIe slot
I connected the two 6+2 power cables from the PSU to the GPU
With the DC cable and the MOLEX adapter, i've built up a power connector for the AKiTiO (as described here in the forum)
I prepared the ATX adapter for the paper clip trick
After this steps, i connected everything together and so i've got my eGPU in the "ghetto-mod" version
I connected the TB2 cable (included within the AKiTiO) and switched on power at the PSU
Then i've turned on my iMac (now the blue LED at the AKiTiO lights)
For the driver installation, i've downloaded the script: https://www.techinferno.com/index.php?/forums/topic/7989-script-automating-the-installation-of-egpu-on-os-x-inc-display-output/
I've followed the instructions in the thread. This script is doing the installation automatically (thanks to goalque for this amazing work)
After the first try, I've got the message "nvram: Error getting variable - 'csr-active-config': (iokit/common) data was not found"
To solve this, the SIP has to be switched off (csrutil disable) when using MAC OS X El Capitan (here is a link http://www.macworld.com/article/2986118/security/how-to-modify-system-integrity-protection-in-el-capitan.html)
Then i boot up my system and installed the latest CUDA driver package from NVIDEA
I started my 3D program and the external GPU was recognized directly. I did a few test render,, the performance was great :-)
Then i connected an external monitor to the eGPU via a HDMI cable and after i made the external monitor to my primary monitor (https://support.apple.com/en-us/HT202351) everything works fine.
The whole project has lasted one week. The system runs very stable and the fans are very quiet. Many thanks to this forum!
The next steps will be:
finding a suitable case for my PSU, AKiTiO and GTX
upgrading to OS X 10.11.3 and the latest NVIDEA driver
installing Windows 10 (via BootCamp) and make the eGPU running under Windows
I have just updated to MAC OS X 10.11.3 and NVIDEA Web Driver 346.03.05f01 (incl. CUDA Driver Version: 7.5.25). Everything works fine.
A few days ago, I also installed Windows 10 /with Bootcamp). I followed the instructions (and the power up sequence) by ZapCord and everything works fine.
The eGPU will be recognized and i am able to do fast renders.
On the external display, the eGPU works brilliant, only OPTIMUS will not work.