I tried accurate vbeam emulation in a lot of games at some point and my conclusion was that either it slows the game down a lot or more often does seemingly nothing while the emulator reports an improved speed. The bit about audio timings is interesting though.
Windows 7 64bit
Intel i5-2500k@4.5GHz
8 GB DDR3
Radeon HD 6950
Intel i5-2500k@4.5GHz
8 GB DDR3
Radeon HD 6950