Don't know if this has been covered before, but...
I have a song with a couple of VST-instruments outputted to different effects. There's no problems when I play the song, but when I try to save it and it gets to a part where the VST-instrument is cut or otherwise silenced it gets REALLY SLOW. Like 5 kb every 7 seconds.
I noticed a similar behaviour with effects on my old computer, with an earlier version of MPT; when I played a song and a channel with an effect got silent the performance dropped to un-playable.
I have no idea what is causing this, but if you could post the simplest possible mod that shows this behaviour and check if it only happens with certain plug-ins you will make it infinitely less difficult for the developers to fix it.
From your story, I make up that you try to export as wav file, am I correct? This would really change the picture than if you'd try to save the module itself.
we need more information on this, like speed-focus said, try to narrow it down to one vsti.
well, if you cant figure out whats causing it, or cant live without that particular vst, you can try using a wav writer vst, like 'tapeit', just put it in the last effect slot, and set it to master, then play the song.
I have seen this when writing to WAV with some synthedit plugs (e.g. PD3) and haven't successfully debugged it yet. As kindly stated by the others, can you confirm you are saving to WAV, and list the plugins involved (preferrably having narrowed down to the specific plug(s) that cause the issue.. bypassing a plug before rendering to WAV will help with this).
Sorry, must've been tired when I wrote that. Yes, i'm saving to wav. And, coincidently, i'm using PD3. :P
I think I'll try a wav writer. Thanks!