Unigine has introduced the Valley benchmark GPU stress-testing tool. Works on Windows, Linux and Mac OS X. For ATI/AMD Radeon HD 4xxx and higher, nVIDIA GeForce 8xxx and higher, and the Intel HD 3000 and higher graphic units. A notable difference between Valley and the previous Heaven benchmark is that there is no tessellation setting in Valley.
Apart from benchmarking, it is possible by changing the Camera mode to Walk to explore the virtual landscape on foot. This landscape according to Unigine consists of "... 64 million square meters of extremely detailed, seamless terrain. The forest-covered valley surrounded by vast mountains amazes with its scale from a bird’s-eye view and is extremely detailed down to every leaf and flower petal...". Selecting the Free or Walk modes under the Camera setting also activates the Environment setting that allows user-controlled dynamic weather.
Further details and free download from here