I have 6470b also. I'm running GTX 1060 6GB on EXP GDC V7 (Expresscard) with XFX 550W PSU and haven't tested gen1 but It's unstable at gen2 speed. When I game the screen goes black for like 3 seconds then it goes back to desktop (Windows 7) With Nvidia kernel driver... message popping sometimes. I'm using it for two weeks so it's hard for me to tell where's the issue, tested already on three different PSU's (400W, 500W and now on XFX 550W) Sometimes I game for couple hours and it's stable and sometimes it hits very often after 5, 10 minutes even.
My system specs:
MOBO - QM77
CPU - i7-2860QM
RAM - 16 GB
IGPU - HD3000
PCIE HARDWARE - WWAN Broadband adapter
DSDT Override - YES
eGPU SETUP 1.3 - I only set PCI COMPACTION to EGPU then 32 bit to NONE and thats it, on this setting it lastet for 2 hours of heavy gaming and then black screen - 3 seconds - desktop.
Fix: It was EXP GDC V8 my bad.
Ok I did all the steps necessary I think. Gigabyte have returned my Graphics and they said the card was working correctly during they tests. I've sent an email to bagget.com customerservice. Hope they will send me a new correct EXP GDC adapter then.
