Jag har ett ST Audio ljudkort, men jag kände igen det här med inbyggd GM och latency.
Från ST Audios Knowledge Bank:
http://www.staudio.de/kb/english/2000xp/index.html
"Windows 2000 and XP both contain the so-called Microsoft GS Synthesizer. This software synthesizer emulates a simple Roland GS sound module. The sound quality is not excellent but OK to listen to GM/GS MIDI files. Sadly, the latency of this software synthesizer is too high to use it for music creation inside a sequencer software. The offset / delay to other tracks is simply too big. Even worse: the software synthesizer is not only unusable for music production, it also can cause potential trouble."
Verkar tyvärr inte finnas någon lösning...