OK - well, turning up the latency by making your ASIO Buffer Size bigger will help for mixing and mastering, where you have finished tracking, BUT you will quickly discover that you could not realistically record tracks with that high a latency.
Once you get to a latency of somewhere over 10 milliseconds - like maybe 15 or more, you will begin to hear a lag between when you hit a note and when you hear it play through Sonar.
BUT, for mixing purposes, you do not care about that lag, as you are only playing things back. So, for mixing/mastering, you pretty much WANT to have your latency high enough to allow for the extra processing needs of the kinds of plugins that sound soooo good - those that use look-ahead processing or lots of CPU.
SOOOO, this will forevermore be something you will have to switch back and forth on - lower latency for tracking, and higher latency for mixing and mastering.
Another factor in the equation is how hard your computer has to work at keeping a low latency and still avoiding dropouts - a balance is needed between performance and sound quality.
Bottom line: you need to find settings that work for recording purposes, and then afterwards for mixing and mastering you will need to bump those settings up to a much higher latency (which is fine, it's just how it all works).
On MY system, I find that the best balance for low latency for recording is:
Audio interface: Sample Rate either 44.1 k or 48 k, (I use 48 k), ASIO Buffer Size of 128
Sonar: Driver Mode of ASIO, Sample Rate of either 44.1 k or 48 k (must match the interface's setting), Record Bit-Depth of 24 bits.
With the above settings, I have an ASIO-reported Total Roundtrip Latency of 9.7 milliseconds, which allows me to record with a zillion tracks and soft synths without hearing any crackles, pops, or having any audio dropouts.
I believe you should shoot for a Total Roundtrip Latency value of at or just under around 10 milliseconds, for good sound quality for recording tracks.
Again, once all the tracks of a project are recorded, and I start the mixing process, I turn the ASIO Buffer Size way up, and that allows me to then add in a bunch of heavy-duty effects plugins and still not hear audio dropouts and such.
I hope some of the above explains some of this to you, and that you find the above settings helping you record tracks without dropouts.
Bob Bone