1. Almost completely redesigned psychoacoustic model, with better PNS implementation
2. Better bit-reservoir management and bit allocation
3. Completely new TNS algorithm
4. New "fast" encoding mode - which is 15.4x real-time on P4 1.8
5. Much more MMX/SSE/SSE-2 optimizations
6. Direct support for MP4 file format
7. Medium quality preset, with 32-bit floating point arithmetics, quallity is only little bit worse than "high" - but the speed is 30% higher (sometimes even more)
8. Overal speed optimizations of the algorithm - 100% faster execution speed