Can I SLI GTX 760?
Yes you can. The requirement is that both cards for SLI be the same GPU (IE GTX 760).
Is the GTX 770 good for gaming?
The ASUS GeForce GTX 770 is a solid gaming solution.” “GeForce GTX 770 Is The Video Card to Get. The GTX 770 is certainly the winner in the price-performance battle. It’s a great upgrade from the GTX 570/580 and even offers substantial performance gains over the GTX 670.
Does the GTX 770 need external power?
Splendid. A good quality 550W power supply is plenty for your system. GTX 770 draws 230W. This is spread over the PCI-E slot (up to 75W) a 6-pin PCI-E power connector (up to 75W) and an 8-pin PCI-E power connector (up to 150W).