EVGA's GeForce GTX 680 Classified is a beast. The card combines a hot-clocked GK104 GPU with 4GB of RAM on a custom circuit board with 14-phase power delivery circuitry. An oversized blower keeps the thing cool, and there's a port for EVGA's EVBot remote overclocking tool—well, there was when we saw the card at Computex earlier this year, anyway. In the EVGA forums, Product Manager Jacob Freeman confirms that the EVBot functionality has been removed from the card "in order to 100% comply with NVIDIA guidelines for selling GeForce GTX products." Voltage control, even via an external device like the EVBot module, is verboten, Freeman says.
Overclockers.com was the first to cover the story, and Bright Side of News has done some further digging. Turns out voltage control limits are part of Nvidia's Green Light program, a certification process designed to ensure cards meet certain requirements. According to Nvidia Senior PR Manager Bryan Del Rizzo, overvolting is supported "up to a limit," in order to "protect the life of the product." Del Rizzo claims Nvidia won't stop graphics card makers who want to overvolt their products wildly or want to provide users that freedom via voltage controls. However, doing so disqualifies products from receiving warranty support from Nvidia. Add-in board makers are free to provide their own warranty coverage, of course.
EVGA isn't the only graphics card maker to run afoul of the Green Light program's rules. MSI's GeForce GTX 680 Lightning Edition card reportedly offered users too much leeway to tweak voltages and had to be scaled back to comply. Del Rizzo notes that MSI chose warranty coverage over extreme overvolting support, just as EVGA appears to have done with its Classified card. He also says those choices have no bearing on how many graphics chips are allocated to the card makers.
If the only penalty for deviating from Nvidia's prescribed voltage guidelines is the loss of warranty support for that product, it's hard to fault the policy. AMD and Intel certainly aren't expected to provide warranty support for CPUs running far beyond stock speeds and voltages. Enterprising modders aren't being prevented from busting out soldering irons to perform their own warranty-voiding voltage mods, either.