MIDI stammering despite resource headroom

[TOTAL]

I've just bought VirusTI.
My present gear is athlon2500+, 512RAM (sufficient, trust me), winxp, cubase sx1 and 2 (I mostly use v1), Novation X-station, lots of VST and Virus.

I have some impressions related with MIDI on this DAW.
MIDI is an old technology, invented when computer processors were thousands times slower, and that's why I think something may be wrong with coding of either cubase or virus (the former unfortunately won't be improved in this version).

The thing is
xp tweaked for optimum perfomance, background services, etc, unused services switched off, gadgets and animations off, cleaned with win doctor, not more than 3% of resources usedbefore starting cubase

cubase tweaked for midi and stability
low priority for audio, high latency

no vst in the project, no extreme midi complexity



BUT at 8th track, while recording the system occasionally stammers. Thus the note currently played gets interrupted, mind gets distracted.

The cubase's performance monitor shows not more than 7 out of 100.


I'm starting to think that for live midi multitimbral performance, the idea which appeals to me best, hardware might be the only way.

An alternative is an even faster computer. questionable because:
1. having a twice a fast daw I would surely look for some more powerful=more demanding host (like sx3)
2. it is not an issue of power but stability (those disturbing peaks are not even noticed by cubase's vst or harddrive performance bar)
3. ram is sufficient and stable: 80MB free, no peaks


Maybe it is those windows services (I have several ON like printer, dial-up related, although quicksearch is OFF.
I wonder if it is possible to start another windows user and dedicate it for office matters and this one I currently have -> dedicate for music, eg cut all unnecessary services, remove all processes.
By the way, is there a list of windows services which are essential for music applications? Can the settings be made different for different users? Could system restore function operate only in this other user?