I have a Radeon Pro Duo with GPU2 stuck at 100% usage at idle. Temps are 40-45 idle at normal fan speed, then low 30's with full fan. Games still seem to run fine, but they may be relying on GPU1 for most of the processing. I've used Sapphire Trixx, CAM, and AMD Overdrive to view GPU load. All say 100%, I run at stock speeds, 1000Mhz clock and 500Mhz ram. Using process explorer the actual GPU usage reported by processes was 10%. Most of which came from the VR Compositor.
I had this problem on 16.7.x then when I upgraded to 16.8.2 it went away. Then when I was in SteamVR the driver crashed and recovered. After that 16.8.2 was 100% usage on GPU2 also. I updated to 16.8.3 and unfortunately it didn't fix the 100% load. I'm going to completely uninstall the driver and reinstall and also try with and without SteamVR/Vive software installed.
If anyone has any suggestions let me know. I'll report back with the driver and SteamVR/Vive testing.
OS: Windows 10 Pro
CPU: AMD FX-9590
GPU: Radeon Pro Duo
MotherBoard: ASUS ROG Crosshair V Formula-Z
GPU Driver: 16.8.3 (hotfix)
So I did some further testing. I completely shut off computer. Unplugged the HTC Vive, booted up and GPU2 is now at normal usage. (o.O) Hopefully this helps some other people out there. Also hoping the issue with the AMD drivers and SteamVR gets resolved. Since the Pro Duo is the premier card for VR.