alexoosthoek wrote:

Did you try THIS  ?

To the original poster - don't bother with this link, as DPC Latency Checker is a Windows only program.

However, pops in your audio suggest that your computer's CPU is being interrupted by the Mac OS every so often, resulting in the pops.  Your first action should be to increase the latency in the Fireface "Settings" application.  If you read through some of the posts on this forum, you'll see that a lot of people encountered pops and other performance issues when they switched from Leopard to Snow Leopard.  You could use Activity Monitor (in your Utilities folder) to see if you can track what is causing the periodic high activity, and then somehow disable it, or you could wait for RME to come up with a new Mac driver for the Fireface.