If you are using Soundblaster Live or Audigy cards you should use the ASIO driver from www.kxproject.com (wdm/ASIO driver). The sample rate must be set to 48khz, which is the internal rate of these cards.
/Soeren
I'm trying to prepare a concert to show Pd to multimedia students. I just checked what machines I'll have for that and it seems no one has an asio driver for the sound card (all SoundBlasters, I gather). So evidently the latency is up to 200ms or so. Any chance to reduce that without asio? What cards do have asio drivers, and are they easy (cheap) to come by?