@Abstrax :
Are you sure that this is related to 1.11 and doesn't happen in 1.10 for example? I can't think of any change that might cause this issue. Could you maybe try to explain exactly what is happening? How does Octane behave if you switch to a new (empty) project via File -> New... ?
EDIT : I just understand that I have not noticed the problem with 1.10, because the short period I used it I worked on a small scene of 250MB only.
So, I am almost sure that you are right : the problem probably appeared with 1.10.
Switching to an empty new project gives the same problem. I first thought that it was safer to close completely octane before opening a new project to help memory purge, but I get often a freeze as well : the memory charge stops decreasing around 60-50% in Win7 ressource manager. The mouse cursor is busy and the screen turns white.
This occurs on big scenes (my current project is around 2.2GB in 1920x1080). Small scenes of some hundred MB don't show the problem.
My rendering cards are GTX 580 3GB, but the display card is a GTX 260 (PreFermi ?) Does it has an importance in Octane Behavior ?

Before you ask : I can't provide the scene.
French Blender user - CPU : intel Quad QX9650 at 3GHz - 8GB of RAM - Windows 7 Pro 64 bits. Display GPU : GeForce GTX 480 (2 Samsung 2443BW-1920x1600 monitors). External GPUs : two EVGA GTX 580 3GB in a Cubix GPU-Xpander Pro 2. NVidia Driver : 368.22.