RKelley

I'll chime in here as well. I started with a similar setup (15-inch, Mid 2012 - OSX Sierra 10.12.1), Akitio TB2, evga 750Ti GPU (non-powered). Like you found, the unpowered card ran into a ton of problems. OSX would randomly crash for no reason (5mins - 15mins; did not matter). I hacked the vBIOS of the card to lower the clock but still had problems. I returned that card and got an Asus GTX 750Ti card but the display ports wold not show up properly in OSX (worked great in Win10). I returned *that* card and got this card from Amazon (Gigabyte GV-N75TWF2OC-4GI). I paired it with the Dell DA/2 PSU (custom made power cables). The new combination worked really well for a while then crashed again running Valley benchmark. It seemed anytime the onboard GPU tried to output on the external monitor bad stuff would happen (jerky screen, kernel panic, etc). Per another thread, I downloaded and installed the "DisableMonitors" Mac App to temporarily disable/enable the onboard Mac screen. This app seems to have fixed the GPU switching issue. So far, rock solid. Valley plays at 30FPS at 2550x1440, my VM does not crash, and all seems good now. As an aside, I found the Apple Bluetooth mouse to cause some weirdness. Even if the system has been running rock-solid for a while, I get kernel panics if the mouse gets un-paired then re-paired too many times. Seems to only happen with the TB2 setup. I don't use the BT mouse anymore. If anyone is reading this thread, here is my recommended parts list: Akitio TB2 Dell DA/2 PSU with appropriate power cabling Gigabyte GTX 750Ti card listed above (not ASUS as the display ports won't work properly - don't get ATI cards as those have problems with the Akitio unit). Use the automate_GPU script on this site to get the Nvidia drivers installed/loaded, and then use the DisableMonitors tool to make sure the GPU outputs properly to the external display. Sounds complicated but it's not. Hope this helps someone.

FYI - I was running into the exact same issue (OSX 10.12 Sierra, mid-2015 MBPro, Akitio eGPU with EVGA GTX 750Ti [w/out 6-pin power]). I was trying to run the Heaven benchmark on the external monitor and was getting awful performance (12FPS). Here is how I solved it: Open Control Panel - Power Savings --> Disable Automatic Graphic Switching Disconnect the DVI cable from the eGPU card, wait 1sec, plug back in Re-run Heaven on eGPU at High Settings (2550x1440) - 30FPS! BTW - You can tell which GPU it is using by looking at the temperature number in Heaven. The internal GPU runs 50-60degC and the eGPU runs 40deg. Hope this helps someone!

Thanks for the reply. Looks like the ATI R9-2xx cards are definitely a no-go with the AkiTio unit. I will look for an Nvidia card instead.

Having similar problems like the OP; my 750Ti becomes unstable after a while on OSX while doing heavy GPU tasks. Question: instead of underclocking the GPU (via custom BIOS), can a powered PCIe riser card solve the power problem? If so, which riser card do you guys recommend?

Prior to Sierra, the nvram boot-arg for Nvidia was "nvda_drv=1"; now it is "NvidiaWeb". Download, edit the eGPU setup script from @goalque - search for: boot_args="nvda_drv=1" Change the "nvda_drv=1" to "NvidiaWeb" in all occurrences. Save, exit, then re-run the script. Otherwise, the Nvidia drivers will get loaded but not run on boot.

Looking for some help/guidance. I have a mid-2012 MBP (16G RAM, 2.6GHz i7, NVIDIA GeForce GT 650M 1024 MB) running El Capitan 10.11.6. I purchased an Akitio TB2 enclosure and paired it up with an MSI R9-290X card and a BFG 500W PSU. I hooked up everything, ran @goalque's eGPU setup script, rebooted, and was able to get my video card properly recognized as an AMD 4000 GPU. Yah! However, after some time (about 15mins), the system becomes increasingly slower to the point whereby I have to power cycle my system. I have not pinned the problem down to a specific set of actions, however, I suspect it happens when I start playing videos or moving lots of screens around. I see a bunch of messages in the console like this: "surface testing disallowed updates for sequential attempts". I switched out the GPU for an R9-270x, disabled automated graphic switching in System Preferences, and even tried the same setup with Sierra; same problem. Wondering if anyone here has had similar experiences. I just can't seem to get a stable system running...

Yes, the existing script by @goalque still works fine. It needs an "adjustment" to work in Sierra (namely the nvram boot args), but it works well. I used it both in El Capitan and Sierra today.

Greetings all, After reading tons of threads on this site (awesome info!), I ordered an Akitio Thunder2 box with a 2M thunderbolt cable. I have a spare R9-290X card which requires 1x 6Pin and 1x 8Pin connectors to use as a test. From what I have read, the 6-pin pulls 75W and the 8-pin pulls 150W. Thus, I need a 235W PSU (225 for video card and 10W for Akitio unit). Is this correct? If so, is there an external "brick" I can use to power this setup? While I do have an normal PC PSU, I would much prefer to use one of the brick units (Dell DA-2, etc) to keep everything looking good. Once everything is running well, my son is going to CAD a custom box and make it in his fab lab.