Well, I got rambunctious and went ahead and jammed the GT610 in there. It means I can't put the chassis cover on, but it suffices to do a quick test.
Compared to the HD2000 graphics with my i3, the FF/REW and video overall seem to be improved with the GT430. Surprisingly I still get periodic audio dropouts with Dolby True-HD... this could be due to my using the "sync to display" XBMC option, but no other audio formats are having trouble. Setting True-HD to disabled and sending it as PCM is a viable workaround to this problem.
This card does support 23.976, and in very limited testing, I do not appear to be getting dropped frames. Like the Intel card the speed of frequency changes is admirable, with just a quick hiccup, not the long pause I get with the ATI card under Windows.
I have a motherboard that has an Intel ICH2 header (which my ICH2 IR is plugged into) and I was delighted to discover that the MPC remote "power togglef" command actually power the system on and off perfectly with OpenElec. This was always irritating under Windows because Windows power management would just put the system to sleep instead of powering off (which is what I want).
Overall this is really growing on me. Two questions.
1. Can anyone recommend a lower profile silent (or very quiet) Nvidia card that supports HD Audio?
2. Can anyone PM me information about doing retail BD playback with OpenElec? I understand there is a file I need to install on the system to do this and I'd like to test it.
At this point I think I'm going to test this out for the next few days to see how the audio and video quality hold up during regular viewing. At that point, if it is solid, and if I can find a good Nvidia card that fits in my case, I think I'm going to switch over to OpenElec. I am becoming very impressed with it.
To answer Dark_Slayer's questions;
If you are using the WMC profile, you do not need the "Remote sends keyboard commands" option enabled. Everything feels snappy with my WMC remote or Flirc using WMC keyboard equivalents. I never enable "Remote sends keyboard commands" which may be the difference
Under windows I would turn this on because I had my Harmony set to send a combination of Windows Media Center remote commands (keyboard buttons) as well as the standard WMC remote commands. For example, I have a button labeled "diagnostics" on my harmony that sends the "o" keyboard button so I can check frame-rate sync, etc. It does not look like this will work under OpenElec so I will disable it and learn to live without it. My IR sensor sits inside my PC case and is not super sensitive so that might also be affecting things.
Is your i3 using a fanless heatsink?
Nope, just using the stock HSF.