Since I did the latest Omnisphere upgrade, my playbacks are freezing and I am getting the Logic "system overload" message. I just upgraded to an IMac 27 quad core, and was distressed to get the message on the new machine. When I monitor cpu usage, I'm only using 6%, so I suspect its an Omnisphere issue since I don't get it in Logic otherwise. Any ideas or suggestions? I was about to add 4mb ram but I'm concerned that won't help.

27" Imac quad, 4 mb ram, Logic 8