Upon launching this game via. the Steam library, choose "Hitman: Blood Money Configuration" (can be also found in C:\Program Files (x86)\Steam\steamapps\common\Hitman Blood Money\ as the "config.exe" file) and under the SLI section in the new window, tick both boxes: Override SLI AND Enable SLI.

Even though the use of SLI is related to having two graphics cards... some single graphics cards seem to get much better performance and shorter loading times from the option with this game (which a number of threads for this game confirm -- with no apparent side effects). I hope this helps.