Possible driver bug if VRAM and RAM are full and context switch happens

Hello everyone,
I have a problem which happens if the RAM and the VRAM are both more or less full (I think it is enough that VRAM swaps to RAM and RAM to harddrive) and the OpenGLContext is switched from one thread to another one. Then OpenGL stops reacting, the commands are not executed anymore. There is no exception, error, warning in that case and “wglMakeCurrent” returns TRUE.
If the video ram or the normal ram are not full there is no problem, so context switching in general works. If both rams are full and everything runs in one thread (no context switching) everything is slow but works.
I am curious if someone had this problem before or can say something to this.
The thing I am wondering about is that no warning/exception or whatever that tells me that there is a problem, OpenGL just stop working.
My enviroment:

Windows 7 64 bit
Intel Xeon E3-1270
Quadro K2000 with driver 355.85