NVIDIA has announced that Forceware 340 series is the last to support OpenGL 3 hardware. This implies that no more new OpenGL extension will ever be supported by NVIDIA OpenGL 3 hardware even if it could have been implemented. Thanks to NVIDIA commitment so far, the OpenGL 3 hardware implementation supports more than 60% of the OpenGL 4.4 extensions. NVIDIA had an amazing run with its OpenGL 3 hardware especially with the G80 that was in my opinion the most innovative and crazy GPU architecture ever released.
AMD has give up on its OpenGL 3 hardware 2 years ago already so that no OpenGL 4.4 or OpenGL 4.3 extension is supported. The convenient aspect is that by now AMD OpenGL 3 hardware market share is not significant which is less work for OpenGL programmers. I am not sure the users agree.
The final report for the OpenGL 3 hardware supported extensions is available for download. We had a good run little beauties.