When you open Photoshop, the following unsupported graphics hardware dialog appears, and 3D or other functionality is unavailable.
Upgrade your graphics card. The minimum amount of graphics processor VRAM supported for Photoshop is 512 MB (1 GB or greater of VRAM is recommended).
If your graphics card already has 512 MB of VRAM, but you still get this error, update your graphics driver. Updating the driver can help ensure that Photoshop can access all the VRAM.
Photoshop will open and operate with 256 MB of VRAM. However, 3d and other graphics processor enhanced features aren't available for use if you have less than 512 VRAM (1 GB or greater of VRAM is recommended).
For detailed instructions on troubleshooting graphics processor issues, see Graphics processor (GPU) troubleshooting.