I did a number of further comparisons, as posted in the thread, including taking the same Oppo dedicated analog stereo output and running it through Ext In inputs on the 4310 so it went directly to the analog output stages, then to the ext amp. That produced SQ that was not as good as the dedicated stereo preamps and I attributed that to the better preamp sections of the dedicated preamps.
I then instead ran that stereo out through std stereo inputs on the 4310, sending it through an additional ADC, Audyssey and DAC. That was to my ear better than Oppo HDMI to AVR. I attributed that to the Oppos better DAC, but perhaps it had to do with less jitter being introduced. I don't know. But I left it hooked up that way for Stereo music listening until I got my AVRA100/4311. Then I just didn't seem to hear much of any audible difference of HDMI vs analog/DSP. I attributed that to an improved DAC/preamp section, etc. in the newer AVR. Further, no longer could I hear any loss of detail with DSP and I attributed that to improvements of XT32. I then abandoned the analog stuff and invested in Audyssey Pro and got a nice boost in SQ. Conclusion : in my room, DSP RC trumps all.