Yes, the TX650v2 supports SLi. I'm not sure what kind of "support", you expect it to give. you. The power supply only needs to supply the electricity. Theres nothing special about electricity as far as the video cards are concerned. The TX650v2 has 2 6+2 PCI- E connectors, it also has 8 molex 4 pin connectors. The 660 TI uses 2 6 pin connectors, and most of them include molex adapters for if your power supply has insufficient PCI-E connections. There is absolutely nothing wrong with using these molex connectors to power a 2nd graphics card, contrary to many "old wives tales". As long as the power supply is of good quality, such as a TX series Corsair, you're golden.