Go to Edit -> preferences -> Performance
and make sure "use Graphic Processor" is Checked
Restart Photoshop and then Try again
What version of Photoshop are you using?
If CS6 or earlier, is it the Extended version? The non Extended version does not support 3D.
Is your system up to the minimum spec for Photoshop 3D ? Scroll down to see the minimum spec in the link below.
Do you have the most up to date driver for your GPU. Note you must source it from the GPU maker's web site.