Unfortunately I don't have unlimited time to test right now. Maybe this weekend I can run more tests in different conigurations.
I would encourage you to try to optimise your settings, because I watched Resident Evil: Extinction and had no Atmos drop outs, which can happen for a couple of titles, as it did when I tested a few LOTR titles, it doesn't mean the issue is resolved. At least it proves that they are not specific to the content, at least here (1:1 rip from original disc to BD folders played with BD Menus).
I took a log during playback and I've emailed it to Nev. Maybe comparing mine (no Atmos audio drop outs) and yours (lots of Atmos audio drop outs) might help him to identify and resolve the issue.
I also tried to use madVR, but with the XPS 17 and the E-GPU, I got lots of dropped frames that I don't get with JRVR. So I also encourage you to do your testing with JRVR. I don't have more dropped frames with madVR in the HTPC, but for some reason it doesn't seem to like the E-GPU as much. It could also be my madVR settings, that are hungrier than JRVR (even set to max quality, which is how I set it).
For this pass, I had disabled the 3060 dGPU and I had also selected DCI-P3 as the target gamut for the tonemapping as I watched the film on the JVC.
Here are the dropped frames I got (as always, I reset the stats during the first minute, until all the initial drops with JRiver have happened, which can take 30 secs to 1 minute):
- 2 after about 2 min. (2/0)
- 1 more after about 15 min. (3/0)
- 3 more in one chunk after about one hour and 4 minutes (6/0). This would have been the Atmos audio drop if the number of dropped frames had been higher.
- 1 more at one hour and 7 minutes (7/0).
Seven dropped frames is a lot more than I would find acceptable, even if in this instance it didn't mean an Atmos drop out. I attach a screenshot showing the stats during the end credits (sorry for the low res, I got the downconvert wrong).
Again, with the 1080ti I never get more than 2-3 per film, and I never get an Atmos audio drop out. Ever.
Finally, I tried to run Latency Monitor while I was playing RE:Extinction. It seems to be unhappy with ACPI.sys and Storport.sys on the XPS 17 with the 3090 in the E-GPU (which isn't surprising as the E-GPU adds a lot of latency, which is one of the reasons why I wasn't sure I'd be able to use this config to reproduce the issue).
Also, unlike the HTPC, the XPS 17 isn't dedicated to video playback, but again it's not an issue with the 1080ti or MPC-BE, so there is a margin of improvement for JRiver MC specifically, even if the issue is linked to the 3xxx or 4xxx and if in my case, for these tests, the E-GPU adds latency. I attach a Latency Monitor screenshot too. Note that I didn't get any audio drop out this time, so latency monitor can't be entirely trusted
Please don't discard my test due to these poor Latency Monitor results. I have the same Atmos audio drop outs issues when the 3090 is in the HTPC (AsRock X570 Creator MB, 5950X, PCI-E 4.0 16x and 32GB RAM) so as long as I can reproduce the drop outs with the 3090, it's a valid test platform.