There is a free program called DPC Latency Checker, and another called LatencyMon. Download and run these programs to see if your computer's current configuration is capable to run streaming audio applications, such as Sonar, without latency issues.
The download link for DPC Latency Checker is:
http://www.thesycon.de/deu/latency_check.shtml And the download link for LatencyMon is:
http://www.resplendence.com/latencymon When you run those programs, do it while Sonar is NOT running, to see what the base level of performance is.
And, independently of that, go into Sonar, load one of the projects you are having trouble with, and just for testing purposes, hit the 'E' key on your computer keyboard. This will toggle off/on the bypassing of all effects. After bypassing all effects, hit play, and see if that fixes the dropout issues. If it DOES, then one or more of your effects plugins is causing your problems. If bypassing the effects does NOT get rid of the issues, then we need to look at some other things - and most likely some info from running DPC Latency Checker and/or LatencyMon will help with that.
Since you indicate it is a laptop, you may be experiencing problems with Sonar's audio streaming caused by the laptop's wi-fi adapter. Often, these for some reason interfere with streaming audio performance. For a test of that, you can go into device manager and temporarily disable the wi-fi adapter and then test your problematic project in Sonar. (you can enable it again right after testing Sonar with it disabled, so don't worry). We just want to see if that is contributing to your problems. So, please review the above, download those programs, test out bypassing the effects, run those programs, test the disabling of your wi-fi adapter, and post back your results for all of that.
Thanks - we'll get it.
Bob Bone