Skinnie and benna, two our forum members, posted some screenshots of the Soldier of Fortune II: Double Helix game, catched by two Voodoo2 SLI based systems, at 1024x768 video resolution: SoF II was fully playable in both cases.
They chose to run SoF II using a high speed processor (skinnie pc configuration includes a Intel Pentium 4 3200MHz Prescott cpu): so the 3dfx Voodoo2 SLI can benefit of a stable data stream from PCI interface and of a sended data immediate elaboration.
About the 3dfx Voodoo2 SLI configuration: you get SoF II runs on 3dfx Voodoo2 and 3dfx Voodoo2 SLI systems with both Windows 9x/ME and Windows 2000/XP OS families. The suggested software configuration is based on the latest FastVoodoo2 driver for own OS bound together to MesaFX or WichedGL external library.
In fact, Soldier of Fortune II has no native support for 3dfx Voodoo2 so you must do a manual installation of MesaFX or WichedGL library in to the game folder to enable it.
Good luck, 3dfx users.