hi, russellvb.

please refer this thread.
https://bitcointalk.org/index.php?topic=2401059.0;all

Windows Update on Jan/3/2018[KB4056892] might fix this problem!
You no longer need HackFlags nor Disable Audio Devices!

If you try install 1709 and patched up to [KB 4056892] and the rig successfully recognized the GPUs well without HackFlags,
I no longer recommend you to use 1703.

ty