I'm no expert but I don't think Sonar x32 can address all the memory. As I understand it that's one of the limitations of x32 versions.
 
I'm running x64 all round so that might be the reason I can and you can't. I'm sure someone who knows more will correct me if I'm wrong.

32bit SONAR cannot see all of your RAM. It will only work with less than half your RAM. You may actually be running out of memory as far as the application is concerned.

I'm not sure but maybe increasing your buffers will free up some memory. Just a thought. Also if you are trying to do what I think you are trying to do the CakeTV webinar on drum production explains using audio snap across multiple tracks. I've even taken it a step further for fixing tempo across a full live band by inserting transients on the non drum tracks. It works but gets definitely gets glitchy. I'm assuming it is a very resource intensive process.