I get clicks and pops when using the Saffire with Sonar.

In the Advanced Audio options in Sonar, under File system there are two options Enable Read Caching and Enable Write Caching--Choosing either of these options lets SONAR use the Windows disk cache while reading or writing audio data. SONAR will usually perform best with all caching disabled, which is the default setting. If your computer has an older IDE disk controller, or a disk controller that does not use DMA transfers, enabling caching may improve SONAR's audio performance. Note: Changes to these settings only take effect when you restart SONAR.