Looks like Nvidia playing at spoil sports again
"Here you can download the MSI GeForce GTX 780 Lightning Power LIMIT BIOS.
This is the 'enthusiast' BIOS for GeForce GTX 780 Lightning owners that free up a couple of limitations.
Simply put the card in LN2 mode and flash this BIOS into it.
After you updated the firmware the Power Limiter of the card can now be set at 300%
Procedure:
Download this version of NVFLASH
Make a USB MS-DOS boot flash drive and place the BIOS and NVFLASH on there
Boot from the USB flash drive into DOS
Make sure your GTX 780 Lightning BIOS is set at LN2 mode
In DOS mode type: NVFLASH.exe V29611L1.rom
After the firmware has been flashed, boot into Windows and download + install the latest MSI Afterburner.
You can now set a 300% Power limit."
UPDATE: THIS FILE HAD TO BE REMOVED AS NVIDIA WAS NOT HAPPY ABOUT IT.
SOURCE