No Panning with Realtek Drivers

I've been slowly working some projects on a new Win10 server, and last night discovered that panning isn't happening at the output. I pan everything right, and I get signal in both monitors. I pan everything left, and I get signal in both monitors. It's annoying. Dr. Google comes up with a lot of references to the RealTek audio drivers, which I use, but no answers. Anyone here seen anything similar?

- Open Reaper's audio device settings (click the string of numbers at the top-right of the main window). Make sure it's using outputs 1 and 2. - Consider using ASIO4ALL instead. RealTek's drivers aren't really meant for audio work, just consumer stuff, so they may not behave properly all the time.

ALC892 works fine for me in Windows 7 64-bit, using WASAPI (or using 32-bit Reaper with 32-bit ASIO drivers, which it has). Stable, low latency, very good sound quality.