http://helpx.adobe.com/photoshop/kb/photoshop-cs6-gpu-faq.html said:
Mercury Graphics Engine
The Mercury Graphics Engine (MGE) represents features that use video card, or GPU, acceleration. In Photoshop CS6, this new engine delivers near-instant results when editing with key tools such as Liquify, Warp, Lighting Effects, and the Oil Paint filter. The new MGE delivers unprecedented responsiveness for a fluid feel as you work.
MGE is new to Photoshop CS6, and uses both the OpenGL and OpenCL frameworks. It does not use the proprietary CUDA framework from nVidia.
...
Tested video cards for Photoshop CS6
Adobe tested the following video cards before the release of Photoshop CS6*. This document lists the video card by series. The minimum amount of RAM supported on video cards for Photoshop CS6 is 256 MB.
Note: Adobe tested laptop and desktop versions of the following cards. Be sure to download the latest driver for your specific model. (Laptop and desktop versions have slightly different names.)
nVidia GeForce 8000, 9000, 100, 200, 300, 400, 500 series
nVidia Quadro 400, 600, 2000, 4000 (Mac & Win), CX, 5000, 6000
AMD/ATI Radeon 2000, 3000, 4000, 5000, 6000, 7000 series
AMD/ATI FirePro 3800, 4800, 5800, 7800, 8800, 9800, 3900, 4900, 5900, 7900
