The Corsair Forum is where many come to get answers about power supplies and other hardware.
I own a TX850V2 which has been very good at powering any hardware I have ever attached to it.
I have gone through so many power supplies due to poor designs and inadequate capacity. The TX850V2 has 60A of 12V current which is enough to start a car, so it can handle any extreme video card available.
I used aa GTX 260 SLI setup and the TX850V2 was rock solid and it did not warm up much either.
The counterfeit AK680 power supply was really a 250W power supply which was sold at a far higher rating that it should have been, That is illegal.
With the TX850V2 I have been able to largely put the saga of the AK680 to bed but the memory of the headaches still linger on. Many have been caught with the counterfeit power supplies.