I don't use Branch Path Tracing with GPU. Separate Process rendering is off.

If you look images closely, you see my GPU, GTX 1070 and W10(Pro, 64bit). W7 isn't option for me, wouldn't use it even if I could. But 373.06 drivers work for now. Too bad I'm using this same PC for playing games too, and those damn things have a bad habit of requiring newest drivers to run optimally.

Something has changed in drivers since 373.06 release, but at what point? There's 2 other versions between 373.06 and 375.95 where I noticed this issue, I haven't tried those because they have other problems.