But if your system can't passthrough E-AC3, DDP has a core AC-3 stream that should go through, same as with TrueHD.

I've decided that I'm not going to worry about it anymore. I'm going to do a mobo upgrade, and that will force me to reinstall Windows 10 Pro, which should give me back AC-3 ...

It does. It lists PCM, Dolby Digital Plus and DTS. Unfortunately, the problem persists. I’ve more or less given up on finding a solution. The system’s a couple months away from a major overhaul, and hopefully a full-scale clean install might help.

Unfortunately that means installing Win10 Pro first ...

I seem to be having a problem with AC-3 Passthrough on WIn11. It's telling me that AC-3 Digital Passthrough is not available. At first I had thought that it was because the latest 24H2 upgrade doesn't have the AC-3 codec or removes it, but I am unsure where to check to see if I have it installed ...