Addictive w/X3 - Problems..

.Just getting up to speed in X3...so far, so good. I hadn't gotten around to trying the Addictive Drums (just continuing so far with what I normally use), but I had ordered the $29 Addictive Keys program and it came yesterday, so I registered and downloaded everything. 
 
Started exploring...the first thing that I noticed after opening up the Addictive Keys was that the system had huge latency (like 300-400 msec). My system is not a rocket, but it's respectable and has always worked well with synths (even TruePiano). I have a separate disc for feed. 
 
I ran a Wave Profiler again, and voila, everything worked fine, for about 15 minutes, when the Addictive Keys developed large latency and gross distortion. Wave Profiler did not help this time. I restarted X3, loaded Addictive Drums this time...again it required Wave Profiler to avoid latency (when I open the Settings window with the Wave Profiler it showed the 4 msec latency from before). Again, it failed after about 15-20 minutes (just enough time to get deep into the creative zone), after which I gave up and continued working (after restart) in my previous way. 
 
Any suggestions? Has anyone experienced this particular fault?
 
jeff
 
Sonar X3 64-bit
Focusrite Saffire Pro 40
SoundCanvas SC55mkii for vintage MIDI
Intel Core Duo 3.00GHz E8400
4GB RAM (sadly that's all it will support)
Shuttle Pro SG31 chassis and MOBO with 7.1 Realtek
Nord Electro as controller, customized Fender-Rhodes Dyno Stage 73 for live keyboard (tube and RNC compressor front end)

Are you updated to the latest X3 patch? (X3b, as of this writing).  Also, it might be necessary to do a VST reset/rescan. 
 
Finally, if VST scan is set to "Background scan", maybe try switching to manual scan.  (I vaguely recall someone having an issue with the bg scan, and switching it to manual solved their problem).