You might try increasing the size of the playback and recording buffers in Edit>Preferences>Audio>Sync and Caching - I upped mine to 512 k each.
Also, can both of you two list your Sonar Driver Mode, as well as your Record Bit-Depth, Sample Rate, and ASIO Buffer Size, and lastly your Total Round-Trip Latency?
Last thing - if you experiencing audio issues, it may be worth seeing if the issues go away if you temporarily Bypass All Effects - by hitting the letter 'E' on your computer keyboard. IF the audio issues go away, with no effects being processed, then it is quite likely that one or more of the plugins loaded into that project are meant to be used in mixing/mastering, and not during tracking.
And, if you have moved onto the mixing phase for that project, you will want to then bump up your ASIO Buffer Size to be super big, as tracking latency will no longer be an issue - now that you are mixing. Having a larger ASIO buffer during mixing is better, as it allows you to use things like convoluted reverbs, which by their nature add lots of latency because they have to read data ahead of what is currently being played, for them to properly process the data through the effect.
Anyways, please do respond with the info I requested above, and maybe there is something that can be adjusted to give you better audio streaming performance.
Bob Bone