In a method of hydroprocessing, hydrogen gas for the hydroprocessing reaction is combined with a liquid feed composition comprising a feedstock to be treated and a diluent to form a feed stream, at least a portion of the hydrogen gas being dissolved in the liquid feed composition of the feed stream, with non-dissolved hydrogen gas being present in the feed stream in an amount of from 1 to 70 SCF/bbl of the liquid feed composition. The feed stream is contacted with a hydroprocessing catalyst, within a reactor while maintaining a liquid mass flux within the reactor of at least 5000 lb/hr·ft2 to form a hydroprocessed product.