OpenGL VSync SwapBuffers 100% CPU core

Hello. When I seperate render in different thread with VSync enabled this thread consumes 100% CPU core while SwapBuffers waiting for sync. Everything works just fine with VSync disabled or in single thread (0 - 1% CPU). Is this way it meant to be or this is NVidia driver bug? Thanks in advance.

GTX 560 Ti
Microsoft Windows 7 64bit

The driver usually yields short delays. This has a lower latency then a proper mutex, but result in a higher cpu usage.

Why when I render and process Windows messages in sigle thread CPU usage is 0 - 1% CPU. But when I seperate render code to secondary thread it consumes 100% CPU core. This is unacceptable. Also seems that ATI and Intel have no such behaviour.

Problem reported in 2009 and still no response from nvidia?