Hi Diki
Not sure how they have done it with the VSTs, (Although interesting that you can only load 4 simultaneously) but with the rest of the instrument it is all controlled by the OAS database, (And from demos so are the VST sounds in OAS 7) and if what you are trying to load takes you over computer specs limitations then it wont allow you to load it.
If you improve your onboard computer specs, you just reload OAS with the upgrade button, (Just as if you are loading an update) and the OAS database matches itself to the new computer spec.
The above is just a basic explanation of how it works, but should give you a general picture.
Regards

Bill


[This message has been edited by abacus (edited 03-15-2008).]