OK, I really hope this will help you use SONAR Plat.
I'd similar issues shortly after updating to Platinum when it was released. X3 played fine, but Platinum had clicks and pops. I thought Line 6, Kore 32bit, 32-64bit bridges, even bought the wonderful Jbridge.
What fixed it for me 100%, TURN OFF -MMCSS- in Preferences/Audio/Playback and Recording.
It was the last thing I tried after a long time troubleshooting. The help file even says leave it on for Win 7 systems - so I ignored it for so long.
I hope this helps you!
Please bakers, can you look into this, if this is an issue? I have UADApollo/UADPCIe system - maybe that has something to do with it?