I have a project with several MIDI tracks playing through several VSTi\'s. 2 Battery, 1 Culture, and 2 Atmosphere. The CPU use is around 20-25% during playback. There is still around 100MB of available RAM. Lynx2 latency set to 1024 samples. In other words, this project is by no means a big burden.
During playback, sometimes the little red LED next to the CPU meter in SX will light up and immediately after the CPU meter will go to zero. I think that LED means max CPU though. perhaps the CPU spike happens so fast that I don\'t see it happen but the LED gets triggered anyway. In any case, I think I narrowed it down to Atmosphere. One of the atmosphere tracks is a strings section. When I mute that track I can never reproduce the problem.
My system is optimzed. I have followed the typical XP audio tweaks. I have separate, fast, drives (ATA100) for apps, audio, and samples. All are defragged. All are indeed working in DMA mode 5.
There are no weird background processes happening when this problem occurs. All my devices have unique IRQs. It happens regardless if I disable the network and my Edirol UM-2 MIDI interface.
I don\'t know if this is an issue but I run into similar problems on my G5 when I do a lot of stopping and playing around the same area with a lot of hung notes. The hanging notes create a polyphony surge of sorts and create such a glitch. It would make sense it\'s happening with Atmostphere since that\'s the VSTi makeing the sustain patches, but i\'ve also had it happen with other VSTi\'s in a similar situation. Try going to the lower right corner in Atmostphere and beefing the polyphony up from what is usually set to around 10 to somwhere in the 20-24 range. Don\'t go too high or else all the notes will start sounding and your CPU will go in a hurry.
Another problem is you can shorten the release of ADSR Envelope. Sometimes if you shorten it then not as many notes will hang over and you can get a much higher polyphony count.