By default 6750M runs 600/800 (core/mem) at 1.00V, however these clocks run fine at 0.855V. This means it is possible to overclock using lower than stock voltage which will enable faster performance and lower operating temperatures (e.g. 750/950 at 0.955V). A win/win situation. You can always choose to overvolt (>1V) for a higher overclock (above 800 core). I'm not responsible for any damage to your hardware as a result of this guide, exercise caution and keep an eye on your GPU's temperature. FINAL UPDATE : ~800/900 @ 0.955V is the best all-round overclock. Performance gains through overvolting and going above 800 core and 900 mem are minimal and not recommended. Tools needed: ATI Tray Tools (ATT) - http://forums.guru3d.com/showthread.php?t=320467 GPU-Z (optional, for double checking) - http://www.techpowerup.com/downloads/SysInfo/GPU-Z/ Right click on ATT in the taskbar and go into Overclocking. Ticking "Include clocks in profile" allows you to save the current clocks as a profile for easy access or for automated overclocking under "Game Profiles". If going higher than 1V, ensure MBP is plugged into magsafe adapter and windows power options profile is set to performance. Press on "Set Default Clocks" to reset card to original state. Only Overclock when needed and never overvolt on battery power. edit 25/4/11 - Max recommended is ~870 core (give or take 10MHz)/1050 mem @ 1.05v edit 27/4/11 - Overclocked 750/950 @ 0.955V running at lower temps than stock 600/800 @ 1V edit 28/4/11 - Cleaned up guide, added osd,hotkey,game profile usage Game Benchmarks Crysis 2 Bulletstorm, 600/900 vs 880/990 on 1680x1048, High Settings, Med Post Proc Go ahead, experiment and post your results + benchmarks !