My SONAR X2 x64 is very stable too!
I had some strange things happen "crash" in the past but I found out how to fix it. If you experice instability with SONAR or other programs, try this out.
First check in Windows event log file? Do you find "error id 46 volmgr"?
'If you do,.... this will fix it!
Let's try these steps to change the settings of virtual memory only for 'C' drive and remove the settings to automatically manager paging file size for other drives.
a. Open System by clicking the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking System.
b. In the left pane, click Advanced system settings. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
c. On the Advanced tab, under Performance, click Settings.
d. Click the Advanced tab, and then, under Virtual memory, click Change.
e. Clear the
Automatically manage paging file size for all drives check box.
f. Under Drive [
volume label], click the drive that contains the paging file you want to change.
g. Select the drive and select no paging file and click set for all the drives except for C drive:
Set page file size as same as your installed RAM size, example: If you have 8126mb RAM set MAX pagefile to 8126 and minimum to same value 8126.
Windows will need to rebot your system..
http://windows.microsoft.com/en-US/windows7/Change-the-size-of-virtual-memory