I'm creating a GL_RGBA16F texture, 4096*4096, mipmapped.

After that, for each mipmap level, I'm creating a FBO and attach the level to the FBO.
This works for all levels down to level 1.
However, for level 0 (4096x4096), glCheckFramebufferStatus suddenly returns GL_FRAMEBUFFER_UNSUPPORTED.

GL_MAX_TEXTURE_SIZE is 4096
GL_MAX_RENDERBUFFERS_IZE is 4096
GL_MAX_VIEWPORT_DIMS is 4096x4096

So, I'm assuming a bug in the driver.
This was tested on a machine with Forceware 258.96 installed on a WinXP64 machine. The gfx card is a GF7950GTX (512MB)