Another +1 on using a real ASIO interface. ASIO4ALL can work, but it can also produce the exact systems described - dropouts, freezes, etc. In many cases it's not enough to have a different driver installed with ASIO4ALL still on the system. I had a friend with a laptop who installed ASIO4ALL, got sick of the problems, and bought a quality interface with well-written drivers. However, he still had problems with the audio interface that only went away when he
uninstalled all traces of ASIO4ALL from his system.
I think if no one used ASIO4ALL, the "SONAR doesn't work" posts in the forum would drop dramatically.
FWIW I haven't had a freeze or crash in SONAR in at least six months. I did have two projects with dropouts, but when the Toast notification popped up saying there had been a dropout, I clicked on Help. The suggestion about changing the hard drive buffer size solved the problem for one project, and saving the other as a bundle file, then re-opening it, de-fragmented that project so it no longer had dropouts.