In my opinion, people who use your encoder first of all care about quality and then speed. So if SSE2 causes some precision loss then it might be worth to drop this optimization. Though it's quite strange that it causes such distortion because untill now there is a common belief that different compilers shouldn't produce noticeable audible differences.I get a miserable 6x speed (non-SSE2 3.100i) on my Atom based netbook with all 4 threads fully loaded , but it's not an issue at all.
I started to test 3.99.5 V1 V0+, 320k as well as the funtional extension builds (3995f). Quality is pretty good with both but unfortunately some problems remain and some are pretty bad.
Thank you for testing.I 'e got a file 'A03_emese.flac' on my pc which contains a 6 sec. track, and I guess that's your emese sample.I've encoded it, and it's clear that the '+' variant can't help here. It consists of short blocks to nearly 100 per cent, so that bit reservoir is nearly always close to empty. So the '+' variants can't provide extra bits for short blocks, and the data space available from 320 kbps frames isn't sufficient here.