When it comes to the performance results, the NVIDIA GeForce GTX 680 performed as expected and we were impressed. Our performance numbers significantly improved and our gaming experience was better! Of the nine benchmarks that we used we found that adding a second GeForce GTX 680 for SLI improved performance on average by 64% at a resolution of 1920x1080 and 84% at 2560x1600. All of our tests showed a larger benefit from running in SLI at 2560x1600, so..."
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips