late-2016 15" MacBook Pro RP460 + GTX1070@32Gbps-TB3 (HP OMEN Accelerator) + Win10 [benhoad]^
I still need to sit down and do a fresh install from scratch to 100% guarantee that this method is able to be replicated but I'll jot down some notes here.
The premise of my setup was be able to keep my MacBook Pro as clean as possible in terms of Windows, such that when everything is unplugged it's a standard pristine MacBook. With this in mind I initially purchased a Samsung T3 500GB external ssd and set it up as a Window to Go drive. The internal RP460 was sufficient for most games on low settings but I really wanted to go the eGPU route as my main desktop had relatively budget internals except for the GTx 1070 FTW graphics card. I'm not a complete stranger to eGPU setups with Windows To Go as I'd successfully managed to build one for m GF using a 2013 Retina MBP + Akitio Thunder 2 + 1050ti sc, however given it's lack of dGPU this process was relatively plug'n'play.
Now, for my build:
1) MacBook Pro 2016 - RP460
2) Samsung T3 500GB - Windows to Go installation
3) HP Omen Accelerator
4) EVGA GTX1070 FTW
5) External PSU for Omen - Corsair SF600 (I'll explain why)
6) Samsung 500GB 850 EVO - for internal Omen game storage.
7) External Monitor/Keyboard/Mouse - Dell U3415W/Corsair k70 RGB/Razer Ouroboros
Initial Hardware Setup
The first issue I ran into with the Omen was with the PCIe power connectors - it's one 6+2 and one 6pin. The EVGA GTX1070 FTW requires two 8pins. It might be ok to get an adapter to convert the 6pin to an 8pin in certain circumstances but given an 8pin is rated to sustain a much higher power throughput than 6pin I felt I should ere on the side of caution and simply transplant my desktop PSU. This worked... ish. The Omen's PSU is ATX, but it's slightly shorter than my desktop's PSU by a few cm. The placement of the logic board's 24pin connector meant that I couldn't mount it correctly and instead had to feed the internal braided cables through the back holes - This was eventually replaced by the purchase of an SFX power supply which also can't be mounted properly for two reasons 1) the cutouts for the cables at the back of the Omen chassis don't align (probably to stop this very modification) and 2) the screw holes are only for Atx but even with a mounting plate the previous issue still stands.
Eventually my intention is to replace my GTX1070 with some kind of AMD card and then 3d print a custom enclosure while keeping the logic board of the Omen.
Initially I followed the general setup of most MacBook Pro Windows installs. Install Bootcamp drivers and uninstall AMD drivers etc.
I have my TB3 cable plugged in from boot, I hold the alt key and select the windows to go EFI BOOT option, this would hang at boot or give error 12 on the 1070.
I followed the basic DSDT override for registry patching in order to get this rectified and it worked flawlessly (flawlessly... ish - I mean Overwatch and most other games worked <_< ). The issue was that because this relied on Windows being in Test Signing Mode certain anti-cheat software packages (e.g. BattleEye for PUBg players) wouldn't let me run the games out of fear I meant be running hacked drivers.
Clover On External Samsung Windows-To-Go drive
I emailed Nando4 for some guidance/help and he pointed me towards this clover DSDT override method to get rid of the need for Windows Test Mode.
Now for the most part I followed this to the letter, however in keeping with my desire to keep eGPU/Windows stuff external I installed Clover to a small partition on my Samsung T3 and didn't change the Startup Disk.
This way I can boot Windows through Clover just by doing the standard holding of Alt at boot. I do however get two EFI BOOT options now (the first being clover and second being standard Windows) - When i do a fresh implementation I'll see if I can theoretically make Windows a standard install and have Clover boot it without it needing to be a Windows To Go installation.
One thing to note: I had to procure an NTFS.efi file and copy it to (Clover Partition)/EFI/CLOVER/drivers64 and /drivers64UEFI/ to get Clover to see my Windows To Go drive. It had some generic Windows legacy option but that didn't do anything except show a white box.
Sorry for the lack of step by step guide only got this working yesterday and I'm just brain-dumping for anyone else who may have bought or are thinking about buying a HP Omen Accelerator to pair with their MacBook. Looking back, the clover method was a lot easier to get sorted than the standard registry patch especially when it came to create the .aml file - but it also has more inherent risk.
I'll be amending this post with images and benchmarks, if there's anything you'd like me to check/try just let me know. For the moment I'm not going to run Mac OS with the eGPU simply because i'd rather use High Sierra with native support even if that means trading in my 1070 for a Vega or something.