Actually, my PC has XP, and I'm not planning on upgrading to Win 7 until GR and Ableton will run on that OS. From what I've read, I thought MS Windows did not provide an ASIO driver for any of their OS, or if they do, it's not very efficient. I understand that using an ASIO driver that bypasses the Windows process helps reduce the latency built into Windows. Somehow, MAC gets around this issue, but MS doesn't.