"Unload instrument when frozen" not working as it should?


I have searched a lot about this issue. Only a few people seem to have that problem:
(I use Cubase 6, latest update installed.)

I have a project with numerous tracks and vst-instruments. My vst-performance goes through the roof :open_mouth:
(Although i use an i7 eight-core 3 ghz with 12GB of ram installed)

When I freeze the vst-i tracks to free up resources, i check “unload instrument when frozen”. Well, my vst-performance goes a tiny bit lower, not much! When I load the project, I see that the tracks keep loading the vst instruments. They flash for an instance in the left top corner of the screen.

I don’t know if this is a bug. Please, is there anyone who experienced this and found a solution?
(And I don’t mean mixing down, importing that audio track, and deleting my vst-instrument track. I want to be able to unfreeze my track and keep editing)

thanks in advance,