I'm a bit of an obsessive troubleshooter, and when I can't figure something out, it really bothers me. But I'm kind of at the point where I could almost settle for knowing if I'm good with ignoring this one.
I'm running a WMC-based setup as follows:
Dell OEM mobo (Inspiron desktop)
Win 7 x64
GT 520 1GB w/ DVI & HDMI
Display 1: Dell 23" LED over DVI - Primary
Display 2: Toshiba 23" TV over HDMI - Secondary
HDHomerun Dual x2 (so 4 tuners total)
I added the TV as a second display recently, which required switching the monitor to the DVI connection. From the day I did this, Windows has been generating Desktop Windows Manager errors whenever I have WMC running on the TV. Usually the degradation / resource contention pair of warnings, but sometimes the "thrashing is occurring" warnings. It seems to make no difference whether I'm watching local content (through Media Browser), or HD Live TV, or internet streams, so it doesn't seem to matter how much is going on in terms of CPU / GPU utilization.
There are no crashes, no visible performance issues at all when this happens. I've put myself through the ultimate torture of boredom by opening up ProcExp system monitors on the monitor, along with temp monitors, and running WMC on the TV, and I can confirm that there is absolutely ZERO "resource contention" going on, and whatever Windows considers to be "thrashing" must be... obscure because I'm not seeing it. (I'm not even sure what "thrashing" means in this particular context.) Everything is not only normal, it's actually performing better than I would have expected. Very low resource usage.
I've done a wipe / clean install of the nVidia drivers. I did an in-place repair install of Windows (actually because of a different unrelated issue, which is now fixed). I've pored over the other EV logs looking for any correlation (driver crashes, etc). Outside of ending up with 10 custom views that will be useful in the future, that got me nowhere. Following the Windows / drivers install, the errors have reduced by about 60% but they are still there.
I don't know how to further test the connection types, for a few reasons - the TV will only take HDMI, and running WMC full-screen on a single display setup disables DWM. But I'm guessing this is a DVI thing. I already know that VGA mode doesn't work according to spec over DVI on this card because it won't activate until the Windows drivers load. This was also true with my previous card, an OEM GT 4xx that had the same outputs. (When I first got that computer, the monitor came with a DVI cable, and my HDMI cable didn't come till two days later, and I never saw the BIOS until I switched to HDMI.) So it wouldn't surprise me if it is somehow related to the DVI connection.
But after all that longwinded rambling, my question is this - if there is no sign whatsoever of an actual problem aside from those errors, do I even need to worry about them? If it hadn't been for tracking down misbehaving Windows Media services last weekend, I probably never would have seen them and then traced them back to adding the TV. But now I can't unsee them. I know how to stop them - simply disable desktop comp when WMC is running - but that still won't tell me why it's doing it in the first place.
But hey, at least my media services are working properly now, after some tweaking.