Quazar released a new version of is NeoGeo emulator for Dreamcast. This version comes with a lot of changes. A few of them are:

Changes in version 2.3:*Dreamcast specific
-No longer uses SDL at all
-Rewrote the sound driver to use spu dma
-Sound is much faster ( less sfx are dropped )
-New draw_fix from fox68k (thanks fox!)
-Faster video rendering (aside from the new draw_fix)
-Up-ported to kos 1.3 (svn 165)
-Rearranged sound timer functions for speed
-Prepared the source code to use FAME
-Sped up CD-ROM file loading slightly

*Core Emulation
-Increased accuracy in sound chips (you will notice better PSG sounds)
-Fixed Read Upload which fixes the crash in Breakers (and may fix more)
-Implemented Rudimentary Bios Vector/Game Vector switching
-Partially fixed frame counter speed
-Added timer read and write access by the 68000
*Misc

-Rearranged main functions for expandability
-Undid all the experimental things of v2.2
-‘Poked’ code everywhere (many small changes)
-A lot of source cleanup

http://www.dcemu.co.uk/vbulletin/showthread.php?s=&threadid=5095