RivaTuner , GPU / VGA Overclocking Utility Software

RivaTuner is a complete powerful tweaking environment, providing you everything you may need to tune NVIDIA GPU based display adapters. The widest driver-level Direct3D / OpenGL and system tuning options, flexible profiling system allowing to make custom settings on per-application basis, both driver-level and low-level hardware access modes, unique diagnostic and realtime hardware monitoring features and exclusive power user oriented tools like built-in registry editor and patch script engine make RivaTuner's feature set absolutely unmatched.
RivaTuner supports all NVIDIA display adapters starting from Riva TNT family up to the latest GeForce 7 series and widest range of NVIDIA drivers starting from the oldest Detonator 2.08 up to the newest ForceWare drivers family.

In addition to complete NVIDIA hardware support, RivaTuner also provides limited support for display adapters based upon ATI RADEON 8500 and newer ATI graphics processors. All RivaTuner's features besides driver-level tuning options are also available on supported ATI hardware.
The RivaTuner Support Forum can be found here. System requirements:

• Windows 98 (updated MFC libraries required), Windows 98 SE, Windows ME, Windows 2000, Windows 2003 Server x32, Windows XP x32, Windows XP x64 edition, Vista x32 or Vista x64 (disabled driver signature checking required). Note: Windows 9x/ME is no longer officially supported since version RC15. It doesn't mean that RivaTuner will not work under Windows 9x/ME, but it does mean that RivaTuner is no longer tested for compatibility issues under these OS.
  
• Any desktop display adapter based on NVIDIA GeForce or ATI Radeon grarphics card. Mobile solutions are not supported.

You can download Rivatuner here http://downloads.guru3d.com/download.php?det=163