sorry, I missed a lot of this thread.
The only thing I can say for sure about emulator vs. x86 real mode is that I don't see any differences in wall-clock-time speed, except in those cases where the emulator is faster.
We did take in some changes, from another project, to reduce memory footprint. I sometimes wish we had not -- I think every problem we've had goes back to those optimizations. It's a little frustrating, and I'm having trouble right now on the sc520 -- user mode testbios works fine, linuxbios emulator does not.
maybe once my problem is fixed, yours will be too ...
ron