Apparently, the issue is caused by a cocktail of bad firmware to complement the board's PWM circuitry, and bad quality PWM components. As an immediate remedy, Gigabyte issued a BIOS update for the affected products. This BIOS, however, will cripple the board's overclocking abilities. The new BIOS will throttle CPU when subjected to extreme stress, to save the VRM. The BIOS remedy is only for those who opt to keep their boards, or don't subject the board to extreme tuning. The other remedy, is to return the board to Gigabyte, for a free replacement when the "right" boards are available.The BIOS updates can be downloaded at Gigabyte's website.
A video of a Gigabyte X79-UD3 going up in smoke during an overclocking session can be viewed at YouTube.