You don't need benchmarks, even GeForce GTX 760 SLI beats GeForce GTX 780. If you have the money, go for the SLI setup (If you have a motherboard that supports atleast 2 PCI-E 2.0/3.0 x16 (In x16 and x8 mode, so it can run in dual x8 mode). Althought I recommend always to choose a single-GPU solution, it's better to spend less that the price of 780 if it's faster. SLI setups are pretty good optimized by NVIDIA. And you need a good processor and a power supply, atleast Intel Core i5-3350P 3.1GHz or AMD FX-8320 3.5GHz and, let's say, XFX Core Edition 650W minimum!