Which Anti Virus program do you have? How much RAM do you have? Because I only have 2 GB of RAM and just a Duo Core 1.66 GHZ processor and if my anti virus program, Microsoft Security Essentials is doing a full scan and I am recording with Replay Radio 9 at the same time - this can cause a slowdown. Solution for me is to tell my anti virus program to scan at a different time when I know Replay Radio 9 will be recording. Also, you can tell some anti virus programs in its settings to use less CPU processing as is the case with Microsoft Security Essentials. Look for it in the Settings tab if you use this anti virus program.