For those of you who are using 8800 GTS instead of non-apple 8800 GT, you can use NiBiTor to reclock your 8800GTS back to its factory higher clock speed and increase voltage back to factory firmware level without using software/registry overclocking (ie, RivaTuner). This way you dont even have to use RivaTuner (although it is great program if you want to overclock your card beyong factory overclocked speed or reference speed). But most importantly you can change back your card's voltage from 1.1V back to 1.15V. You need NiBiTor 4.0, 8800GT32.rom (from this forum), and most recent Nvidia beta driver. 1. verify 8800GT32.rom checksum (under Adv. Info tab) before you start. Ignore integrity red warning as that is from different file size due to OSX EFI which you need to boot OSX 2. change Device id from 0602 to Nvidia PCI-E 8800GTS G92 (0600) under main screen 3. under clockrates tab, enable change amount of active performance levels. recycle levels from 0 to 4 to enable "extra" row. Enter your card's true core, shader, and memory speed from factory. Put 0 for all 3D, Thrtl, and 2D. Mine was 678 core, 1728 shader, and 972 memory. 4. Under Tools select voltage table editor, change entry 1 to 1v, entry 2 to 1.05v, entry 3 to 1.1v, and entry 4 to 1.15 v 5. Under Voltage tab, change "extra" under exact mode to 1.15v. VID mode should automatically change 6. Under temperature tab, fanspeed column should now automatically have 100% for extra, 3d, thrtl, and 2D. If not put 100%. 7. open "fanspeedIC" under temperature tab. Fill into match your original 8800GTS firmware setting. Mine was TCirt = 83, min Duty cycle= 37. Rest were same as 8800GT 8. Save. and done. Just dont change Sub Vendor ID, Sub System ID, Board ID. Otherwise your card wont boot under OSX If you want to overclock higher speed, you should experiment with RivaTuner before overclocking with firmware.