When running 3 GTX 680's in SLI - is there a significant advantage to using the water-cooled versions of the cards? there a good £200 more each with no obvious performance increase?
Yes there is a significant advantage to doing so and if you were running 3 way I would suggest water cooling. What happens because of how close these cards end up normally next to each other is they have there airflow demolished by how close they are. I would waterblock the 680's and connect them to a good/great water cooling custom loop.