You might want to make sure that you have all of the un-needed background processes turned off, those processes could take up some of the RAM and processor causing a delay, I have noticed that more with the PC based systems than with the MAC. I am not sure how many MIDI devices you have plugged into your E-MU 0404, but I have found that the more MIDI devices you plug in that there is some latency. You might want to try getting a M-Audio UNO MIDI to USB cable and try just plugging your Zendrum into it and then into your computer. See if that fixes the latency, if it doesn't, then my guess would be it has something to do with your processor having too much running in the background which will give you that delay. Hope this helps.